The typical Cinder deployment should have
more than just "layering" enabled.
Enable fast-diff, which requires exclusive-lock
and object-map.
Previously, there was code that tried to enable
exclusive-lock when CEPH_ISCSI is enabled, but this
code would not work reliably, since it was doing
addition instead of bitwise-or. Just remove it
since exclusive-lock will be enabled by default.
Change-Id: Idad98cfebf5e3b265316f2b6a3c201b472faa32c
467b4295f2