create trusts.TokenExt response object (#29)

* create trusts.TokenExt response object

* add redelegationcount, redelegatedtrustid fields
diff --git a/openstack/identity/v3/extensions/trusts/results.go b/openstack/identity/v3/extensions/trusts/results.go
new file mode 100644
index 0000000..3d3c7f2
--- /dev/null
+++ b/openstack/identity/v3/extensions/trusts/results.go
@@ -0,0 +1,29 @@
+package trusts
+
+import "github.com/gophercloud/gophercloud/openstack/identity/v3/tokens"
+
+type TrusteeUser struct {
+	ID string `json:"id"`
+}
+
+type TrustorUser struct {
+	ID string `json:"id"`
+}
+
+type Trust struct {
+	ID                 string      `json:"id"`
+	Impersonation      bool        `json:"impersonation"`
+	TrusteeUser        TrusteeUser `json:"trustee_user"`
+	TrustorUser        TrustorUser `json:"trustor_user"`
+	RedelegatedTrustID string      `json:"redelegated_trust_id"`
+	RedelegationCount  int         `json:"redelegation_count"`
+}
+
+type Token struct {
+	tokens.Token
+	Trust Trust `json:"OS-TRUST:trust"`
+}
+
+type TokenExt struct {
+	Token Token `json:"token"`
+}