use tenant in UserPassCredentials if set (#20751)

* use tenant in UserPassCredentials if set

If you have multiple Tenants you need to set the tenant in https://github.com/Azure/msrestazure-for-python/blob/master/msrestazure/azure_active_directory.py otherwise the azure_rm.py call will fail.

see: https://github.com/ansible/ansible/pull/20750

* fixed PEP8 failure

lib/ansible/module_utils/azure_rm_common.py

@@ -185,6 +185,10 @@ class AzureRMModuleBase(object):
                                                                  secret=self.credentials['secret'],
                                                                  tenant=self.credentials['tenant'])
         elif self.credentials.get('ad_user') is not None and self.credentials.get('password') is not None:
+            tenant = self.credentials.get('tenant')
+            if tenant is not None:
+                self.azure_credentials = UserPassCredentials(self.credentials['ad_user'], self.credentials['password'], tenant=tenant)
+            else:
                 self.azure_credentials = UserPassCredentials(self.credentials['ad_user'], self.credentials['password'])
         else:
             self.fail("Failed to authenticate with provided credentials. Some attributes were missing. "