ceph: fix message memory leak, uninitialized variable

We need to properly initialize skip, as not all alloc_msg op instances
set it.

Also, BUG if someone says skip but also allocates a message.
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/messenger.c

@@ -1396,10 +1396,12 @@ static int read_partial_message(struct ceph_connection *con)
 	if (!con->in_msg) {
 		dout("got hdr type %d front %d data %d\n", con->in_hdr.type,
 		     con->in_hdr.front_len, con->in_hdr.data_len);
+		skip = 0;
 		con->in_msg = ceph_alloc_msg(con, &con->in_hdr, &skip);
 		if (skip) {
 			/* skip this message */
 			dout("alloc_msg said skip message\n");
+			BUG_ON(con->in_msg);
 			con->in_base_pos = -front_len - middle_len - data_len -
 				sizeof(m->footer);
 			con->in_tag = CEPH_MSGR_TAG_READY;