libceph: support CEPH_FEATURE_OSD_CACHEPOOL feature

Announce our (limited, see previous commit) support for CACHEPOOL
feature.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

include/linux/ceph/ceph_features.h

@@ -80,6 +80,7 @@ static inline u64 ceph_sanitize_features(u64 features)
 	 CEPH_FEATURE_CRUSH_TUNABLES2 |		\
 	 CEPH_FEATURE_REPLY_CREATE_INODE |	\
 	 CEPH_FEATURE_OSDHASHPSPOOL |		\
+	 CEPH_FEATURE_OSD_CACHEPOOL |		\
 	 CEPH_FEATURE_CRUSH_V2 |		\
 	 CEPH_FEATURE_EXPORT_PEER)