[OpenStack] Add more detail error message

I get same simple error messages "Unable to initialize cinder client
for region: RegionOne" from controller-manager, but I can not find the
reason. We should add more detail message "err" into glog.Errorf.

Author: FengyunPan

pkg/cloudprovider/providers/openstack/openstack_client.go

@@ -28,7 +28,7 @@ func (os *OpenStack) NewNetworkV2() (*gophercloud.ServiceClient, error) {
 		Region: os.region,
 	})
 	if err != nil {
-		glog.Warningf("Failed to find network v2 endpoint: %v", err)
+		glog.Warningf("Failed to find network v2 endpoint for region %s: %v", os.region, err)
 		return nil, err
 	}
 	return network, nil
@@ -39,7 +39,7 @@ func (os *OpenStack) NewComputeV2() (*gophercloud.ServiceClient, error) {
 		Region: os.region,
 	})
 	if err != nil {
-		glog.Warningf("Failed to find compute v2 endpoint: %v", err)
+		glog.Warningf("Failed to find compute v2 endpoint for region %s: %v", os.region, err)
 		return nil, err
 	}
 	return compute, nil
@@ -50,7 +50,7 @@ func (os *OpenStack) NewBlockStorageV1() (*gophercloud.ServiceClient, error) {
 		Region: os.region,
 	})
 	if err != nil {
-		glog.Errorf("Unable to initialize cinder v1 client for region: %s", os.region)
+		glog.Errorf("Unable to initialize cinder v1 client for region %s: %v", os.region, err)
 		return nil, err
 	}
 	return storage, nil
@@ -61,7 +61,7 @@ func (os *OpenStack) NewBlockStorageV2() (*gophercloud.ServiceClient, error) {
 		Region: os.region,
 	})
 	if err != nil {
-		glog.Errorf("Unable to initialize cinder v2 client for region: %s", os.region)
+		glog.Errorf("Unable to initialize cinder v2 client for region %s: %v", os.region, err)
 		return nil, err
 	}
 	return storage, nil