Fix the argument order for openstack client

If there are --xxx argument placed for openstack clients such as
nova, glance, keystone etc, these arguments need to be placed before
the actual command line. Otherwise, the client will raise unrecognized
arguments exception which will make the command execution fail.

Change-Id: I1568f9332accffdfa3a34d8bbd842f707b1a340e
Closes-Bug: #1388147