Automatic merge from release/2.1.0 -> release/2.2.0

* commit 'ca9684b48a2e3eef98a6f96a557ca46cb021df2c':
  修正：region刚启动未获得token时，验证API请求报500错误

pkg/mcclient/auth/auth.go

@@ -123,6 +123,9 @@ func newAuthManager(cli *mcclient.Client, info *AuthInfo) *authManager {
 }
 
 func (a *authManager) verify(token string) (mcclient.TokenCredential, error) {
+	if a.adminCredential == nil {
+		return nil, fmt.Errorf("No valid admin token credential")
+	}
 	cred, err := a.tokenCacheVerify.Verify(a.client, a.adminCredential.GetTokenString(), token)
 	if err != nil {
 		return nil, err