libceph: advertise support for NEW_OSDOP_ENCODING and SERVER_LUMINOUS

All four SERVER_LUMINOUS feature bits are implemented, switch it on!

NEW_OSDOP_ENCODING doesn't mean much for the client (it signifies
support for MOSDOp v6) but needs to be enabled in order to get the
latest (currently v25) pg_pool_t.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Sage Weil <sage@redhat.com>