Make delete_volume in volumes_client.py use **params

I99f9910f75aef095f2bbb37680ee584e52bf82da introduced a new
kwarg to the delete_volume() method. But the correct way to
do this is to introduce a generic **params argument, so avoid
changing the signature of the method too often.

Change-Id: Ifb6731fd893a32bea6c7832236bb26a2eacaf56c
2 files changed