remove mapstructure from blockstorage,cdn,compute,db pkgs
diff --git a/openstack/db/v1/configurations/results.go b/openstack/db/v1/configurations/results.go
index 5128b01..a708abd 100644
--- a/openstack/db/v1/configurations/results.go
+++ b/openstack/db/v1/configurations/results.go
@@ -1,22 +1,19 @@
 package configurations
 
 import (
-	"fmt"
-	"reflect"
 	"time"
 
-	"github.com/mitchellh/mapstructure"
 	"github.com/gophercloud/gophercloud"
 	"github.com/gophercloud/gophercloud/pagination"
 )
 
 // Config represents a configuration group API resource.
 type Config struct {
-	Created              time.Time `mapstructure:"-"`
-	Updated              time.Time `mapstructure:"-"`
-	DatastoreName        string    `mapstructure:"datastore_name"`
-	DatastoreVersionID   string    `mapstructure:"datastore_version_id"`
-	DatastoreVersionName string    `mapstructure:"datastore_version_name"`
+	Created              time.Time `json:"created"`
+	Updated              time.Time `json:"updated"`
+	DatastoreName        string    `json:"datastore_name"`
+	DatastoreVersionID   string    `json:"datastore_version_id"`
+	DatastoreVersionName string    `json:"datastore_version_name"`
 	Description          string
 	ID                   string
 	Name                 string
@@ -31,55 +28,17 @@
 // IsEmpty indicates whether a ConfigPage is empty.
 func (r ConfigPage) IsEmpty() (bool, error) {
 	is, err := ExtractConfigs(r)
-	if err != nil {
-		return true, err
-	}
-	return len(is) == 0, nil
+	return len(is) == 0, err
 }
 
 // ExtractConfigs will retrieve a slice of Config structs from a page.
 func ExtractConfigs(page pagination.Page) ([]Config, error) {
-	casted := page.(ConfigPage).Body
-
-	var resp struct {
-		Configs []Config `mapstructure:"configurations" json:"configurations"`
+	r := page.(ConfigPage)
+	var s struct {
+		Configs []Config `json:"configurations"`
 	}
-
-	if err := mapstructure.Decode(casted, &resp); err != nil {
-		return nil, err
-	}
-
-	var vals []interface{}
-	switch casted.(type) {
-	case map[string]interface{}:
-		vals = casted.(map[string]interface{})["configurations"].([]interface{})
-	case map[string][]interface{}:
-		vals = casted.(map[string][]interface{})["configurations"]
-	default:
-		return resp.Configs, fmt.Errorf("Unknown type: %v", reflect.TypeOf(casted))
-	}
-
-	for i, v := range vals {
-		val := v.(map[string]interface{})
-
-		if t, ok := val["created"].(string); ok && t != "" {
-			creationTime, err := time.Parse(time.RFC3339, t)
-			if err != nil {
-				return resp.Configs, err
-			}
-			resp.Configs[i].Created = creationTime
-		}
-
-		if t, ok := val["updated"].(string); ok && t != "" {
-			updatedTime, err := time.Parse(time.RFC3339, t)
-			if err != nil {
-				return resp.Configs, err
-			}
-			resp.Configs[i].Updated = updatedTime
-		}
-	}
-
-	return resp.Configs, nil
+	err := r.ExtractInto(&s)
+	return s.Configs, err
 }
 
 type commonResult struct {
@@ -88,34 +47,11 @@
 
 // Extract will retrieve a Config resource from an operation result.
 func (r commonResult) Extract() (*Config, error) {
-	if r.Err != nil {
-		return nil, r.Err
+	var s struct {
+		Config *Config `json:"configuration"`
 	}
-
-	var response struct {
-		Config Config `mapstructure:"configuration"`
-	}
-
-	err := mapstructure.Decode(r.Body, &response)
-	val := r.Body.(map[string]interface{})["configuration"].(map[string]interface{})
-
-	if t, ok := val["created"].(string); ok && t != "" {
-		creationTime, err := time.Parse(time.RFC3339, t)
-		if err != nil {
-			return &response.Config, err
-		}
-		response.Config.Created = creationTime
-	}
-
-	if t, ok := val["updated"].(string); ok && t != "" {
-		updatedTime, err := time.Parse(time.RFC3339, t)
-		if err != nil {
-			return &response.Config, err
-		}
-		response.Config.Updated = updatedTime
-	}
-
-	return &response.Config, err
+	err := r.ExtractInto(&s)
+	return s.Config, err
 }
 
 // GetResult represents the result of a Get operation.
@@ -145,10 +81,10 @@
 
 // Param represents a configuration parameter API resource.
 type Param struct {
-	Max             int
-	Min             int
+	Max             float64
+	Min             float64
 	Name            string
-	RestartRequired bool `mapstructure:"restart_required" json:"restart_required"`
+	RestartRequired bool `json:"restart_required"`
 	Type            string
 }
 
@@ -160,22 +96,17 @@
 // IsEmpty indicates whether a ParamPage is empty.
 func (r ParamPage) IsEmpty() (bool, error) {
 	is, err := ExtractParams(r)
-	if err != nil {
-		return true, err
-	}
-	return len(is) == 0, nil
+	return len(is) == 0, err
 }
 
 // ExtractParams will retrieve a slice of Param structs from a page.
 func ExtractParams(page pagination.Page) ([]Param, error) {
-	casted := page.(ParamPage).Body
-
-	var resp struct {
-		Params []Param `mapstructure:"configuration-parameters" json:"configuration-parameters"`
+	r := page.(ParamPage)
+	var s struct {
+		Params []Param `json:"configuration-parameters"`
 	}
-
-	err := mapstructure.Decode(casted, &resp)
-	return resp.Params, err
+	err := r.ExtractInto(&s)
+	return s.Params, err
 }
 
 // ParamResult represents the result of an operation which retrieves details
@@ -186,12 +117,7 @@
 
 // Extract will retrieve a param from an operation result.
 func (r ParamResult) Extract() (*Param, error) {
-	if r.Err != nil {
-		return nil, r.Err
-	}
-
-	var param Param
-
-	err := mapstructure.Decode(r.Body, &param)
-	return &param, err
+	var s Param
+	err := r.ExtractInto(&s)
+	return &s, err
 }