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The ceph_entity_addr erank field is obsolete; remove it.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/mon_client.c b/fs/ceph/mon_client.c
index bb94006..223e8bc 100644
--- a/fs/ceph/mon_client.c
+++ b/fs/ceph/mon_client.c
@@ -88,7 +88,7 @@
 	int i;
 
 	for (i = 0; i < m->num_mon; i++)
-		if (ceph_entity_addr_equal(addr, &m->mon_inst[i].addr))
+		if (memcmp(addr, &m->mon_inst[i].addr, sizeof(*addr)) == 0)
 			return 1;
 	return 0;
 }
@@ -503,7 +503,6 @@
 		return -ENOMEM;
 	for (i = 0; i < num_mon; i++) {
 		monc->monmap->mon_inst[i].addr = mon_addr[i];
-		monc->monmap->mon_inst[i].addr.erank = 0;
 		monc->monmap->mon_inst[i].addr.nonce = 0;
 		monc->monmap->mon_inst[i].name.type =
 			CEPH_ENTITY_TYPE_MON;