Updates to support in Ceph local.conf sample
Updates to support in Ceph local.conf sample

to make user devstack deployment a bit easier.

Since snapshot_support is now on by default for Ceph
backends, enable it in the default share type extra
specs.

Also specify the SHARE_DRIVER so the manila devstack
plugin doesn't think we're running the generic driver
and try to install kernel NFS and samba servers.

Change-Id: I636a047cacba7c5960df15a99fc79a35a818f45d

openstack/manila,openstack/manila