cinder: Increase VOLUME_BACKING_FILE_SIZE

As reported in bug #1920136 the tempest-integrated-compute job has
started to see insufficient free virtual space errors being reported by
c-sch and c-vol when creating volumes. This change simply increases the
default size of the underlying LVM PV used to host these volumes within
the default LVM/iSCSI c-vol backend deployed by devstack.

Change-Id: I965d4a485215ac482403f1e83609452550dfd860
Closes-Bug: #1920136
1 file changed