Description of the problem: the gitlab pr workflow fails to execute in the RHDH UI but succeeds to create a branch in the Gitlab instance.

How reproducible: 100%

Steps to reproduce:

1. Deploy the gitlab-pr workflow on orchestrator 1.6.1-rc2.

2. Execute the workflow.

Actual results:
Failure message in the UI for the workflow (no workflow instance created):
and error messages in the logs (see attached) 
But a branch was created in the Gitlab instance. ** 

Expected results: Workflow should work as expected