Tests: Fix mock for vzstorage remotefs
Tests: Fix mock for vzstorage remotefs

This needs to be added to prevent writing a file
during unit tests.

Closes-Bug: #1659295

Change-Id: Ic03d1254b3187785f276e4f745f3ba230078e017

eharney/cinder,j-griffith/cinder,mahak/cinder,phenoxim/cinder,Datera/cinder,Datera/cinder,mahak/cinder,openstack/cinder,phenoxim/cinder,j-griffith/cinder,ge0rgi/cinder,openstack/cinder,eharney/cinder