ceph-volume: lvm activate: infer bluestore or filestore

ceph-volume: lvm activate: infer bluestore or filestore

No need to require --filestore and/or --bluestore args since we can tell
from the LV tags which one it is.

We can't drop the arguments without breaking existing users, though, so
redefine them to mean *force* bluesetore or filestore activation (even
though this will error out if the tags don't match).

Signed-off-by: Sage Weil <sage@newdream.net>