Nova-lxd requires that our Ceph images only contain the features
supported by the kernel RBD driver, and a discussion on the dev mailing
list suggests that 1 should work fine as the driver level
This commit contains a charmhelpers sync to bring in the new
flag to support configuration sent from the ceph charms.
Change-Id: Iea2e2215cce01efe47adff9ec6743538c92f2437
9fe6a51011