Remove duplicated judgement

This is the same with I3dbe99b31ffb4d971d2ca7b4be21941f6f30d3cb
Because cred_client.create_user already has the judgement
"if 'user' in user:", so there is no need for the caller
to duplicate it.

Change-Id: I97fc39c90e7da094a384ac3e330e435a71313661
1 file changed