ceph: include type in ceph_entity_addr, filepath

Include a type/version in ceph_entity_addr and filepath.  Include extra
byte in filepath encoding as necessary.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 93998a0..4e3e8b2 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1325,7 +1325,7 @@
 	}
 
 	len = sizeof(*head) +
-		pathlen1 + pathlen2 + 2*(sizeof(u32) + sizeof(u64));
+		pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64));
 
 	/* calculate (max) length for cap releases */
 	len += sizeof(struct ceph_mds_request_release) *