ceph: remove unused erank field

The ceph_entity_addr erank field is obsolete; remove it.  Get rid of
trivial addr comparison helpers while we're at it.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/osd_client.c b/fs/ceph/osd_client.c
index a0aac43..80b868f 100644
--- a/fs/ceph/osd_client.c
+++ b/fs/ceph/osd_client.c
@@ -821,9 +821,10 @@
 
 			n = rb_next(p);
 			if (!ceph_osd_is_up(osdc->osdmap, osd->o_osd) ||
-			    !ceph_entity_addr_equal(&osd->o_con.peer_addr,
-					    ceph_osd_addr(osdc->osdmap,
-							  osd->o_osd)))
+			    memcmp(&osd->o_con.peer_addr,
+				   ceph_osd_addr(osdc->osdmap,
+						 osd->o_osd),
+				   sizeof(struct ceph_entity_addr)) != 0)
 				reset_osd(osdc, osd);
 		}
 	}