Fix bug "Invalid OpenStack Nova credentials." on the gate

During the process, when create_userrc.sh tries to creates
certificates and sourcable rc, it assumes that all users have
the same password.

Change-Id: Ifb57a43aad439ffe041e98465719a8a8eceae544
Closes-Bug: #1260723
Merge "Fix bug "Invalid OpenStack Nova credentials." on the gate"