libceph: announce support for straw2 buckets
libceph: announce support for straw2 buckets

Sync up feature bits and enable CEPH_FEATURE_CRUSH_V4.

Signed-off-by: Ilya Dryomov <152d4c5bebf13a5b809d42b4d789cf9d887e6698@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs