Update go dependencies

vendor/github.com/gophercloud/gophercloud/results.go

@@ -90,38 +90,40 @@ func (r Result) extractIntoPtr(to interface{}, label string) error {
 			if typeOfV.NumField() > 0 && typeOfV.Field(0).Anonymous {
 				newSlice := reflect.MakeSlice(reflect.SliceOf(typeOfV), 0, 0)
 
-				for _, v := range m[label].([]interface{}) {
-					// For each iteration of the slice, we create a new struct.
-					// This is to work around a bug where elements of a slice
-					// are reused and not overwritten when the same copy of the
-					// struct is used:
-					//
-					// https://github.com/golang/go/issues/21092
-					// https://github.com/golang/go/issues/24155
-					// https://play.golang.org/p/NHo3ywlPZli
-					newType := reflect.New(typeOfV).Elem()
+				if mSlice, ok := m[label].([]interface{}); ok {
+					for _, v := range mSlice {
+						// For each iteration of the slice, we create a new struct.
+						// This is to work around a bug where elements of a slice
+						// are reused and not overwritten when the same copy of the
+						// struct is used:
+						//
+						// https://github.com/golang/go/issues/21092
+						// https://github.com/golang/go/issues/24155
+						// https://play.golang.org/p/NHo3ywlPZli
+						newType := reflect.New(typeOfV).Elem()
 
-					b, err := json.Marshal(v)
-					if err != nil {
-						return err
-					}
-
-					// This is needed for structs with an UnmarshalJSON method.
-					// Technically this is just unmarshalling the response into
-					// a struct that is never used, but it's good enough to
-					// trigger the UnmarshalJSON method.
-					for i := 0; i < newType.NumField(); i++ {
-						s := newType.Field(i).Addr().Interface()
-
-						// Unmarshal is used rather than NewDecoder to also work
-						// around the above-mentioned bug.
-						err = json.Unmarshal(b, s)
+						b, err := json.Marshal(v)
 						if err != nil {
 							return err
 						}
-					}
 
-					newSlice = reflect.Append(newSlice, newType)
+						// This is needed for structs with an UnmarshalJSON method.
+						// Technically this is just unmarshalling the response into
+						// a struct that is never used, but it's good enough to
+						// trigger the UnmarshalJSON method.
+						for i := 0; i < newType.NumField(); i++ {
+							s := newType.Field(i).Addr().Interface()
+
+							// Unmarshal is used rather than NewDecoder to also work
+							// around the above-mentioned bug.
+							err = json.Unmarshal(b, s)
+							if err != nil {
+								return err
+							}
+						}
+
+						newSlice = reflect.Append(newSlice, newType)
+					}
 				}
 
 				// "to" should now be properly modeled to receive the