Let's expose it in openstack/ instead.

I can't move endpoint location into a method on anything in identity v3, so for symmetry
I'm keeping them in the openstack/ provider directory. I will export them, though, so I
can call them in rackspace/.
diff --git a/openstack/endpoint_location.go b/openstack/endpoint_location.go
new file mode 100644
index 0000000..52c5221
--- /dev/null
+++ b/openstack/endpoint_location.go
@@ -0,0 +1,52 @@
+package openstack
+
+import (
+	"fmt"
+
+	"github.com/rackspace/gophercloud"
+	tokens2 "github.com/rackspace/gophercloud/openstack/identity/v2/tokens"
+)
+
+// V2EndpointURL discovers the endpoint URL for a specific service from a ServiceCatalog acquired
+// during the v2 identity service. The specified EndpointOpts are used to identify a unique,
+// unambiguous endpoint to return. It's an error both when multiple endpoints match the provided
+// criteria and when none do. The minimum that can be specified is a Type, but you will also often
+// need to specify a Name and/or a Region depending on what's available on your OpenStack
+// deployment.
+func V2EndpointURL(catalog *tokens2.ServiceCatalog, opts gophercloud.EndpointOpts) (string, error) {
+	// Extract Endpoints from the catalog entries that match the requested Type, Name if provided, and Region if provided.
+	var endpoints = make([]tokens2.Endpoint, 0, 1)
+	for _, entry := range catalog.Entries {
+		if (entry.Type == opts.Type) && (opts.Name == "" || entry.Name == opts.Name) {
+			for _, endpoint := range entry.Endpoints {
+				if opts.Region == "" || endpoint.Region == opts.Region {
+					endpoints = append(endpoints, endpoint)
+				}
+			}
+		}
+	}
+
+	// Report an error if the options were ambiguous.
+	if len(endpoints) == 0 {
+		return "", gophercloud.ErrEndpointNotFound
+	}
+	if len(endpoints) > 1 {
+		return "", fmt.Errorf("Discovered %d matching endpoints: %#v", len(endpoints), endpoints)
+	}
+
+	// Extract the appropriate URL from the matching Endpoint.
+	for _, endpoint := range endpoints {
+		switch opts.Availability {
+		case gophercloud.AvailabilityPublic:
+			return gophercloud.NormalizeURL(endpoint.PublicURL), nil
+		case gophercloud.AvailabilityInternal:
+			return gophercloud.NormalizeURL(endpoint.InternalURL), nil
+		case gophercloud.AvailabilityAdmin:
+			return gophercloud.NormalizeURL(endpoint.AdminURL), nil
+		default:
+			return "", fmt.Errorf("Unexpected availability in endpoint query: %s", opts.Availability)
+		}
+	}
+
+	return "", gophercloud.ErrEndpointNotFound
+}