libceph: fix uninitialized value when no get_authorizer method is set

If there is no get_authorizer method we set the out_kvec to a bogus
pointer.  The length is also zero in that case, so it doesn't much matter,
but it's better not to add the empty item in the first place.
Signed-off-by: Sage Weil <sage@newdream.net>

net/ceph/messenger.c

@@ -619,11 +619,12 @@ static int prepare_connect_authorizer(struct ceph_connection *con)
 	con->out_connect.authorizer_protocol = cpu_to_le32(auth_protocol);
 	con->out_connect.authorizer_len = cpu_to_le32(auth_len);
 
-	con->out_kvec[con->out_kvec_left].iov_base = auth_buf;
-	con->out_kvec[con->out_kvec_left].iov_len = auth_len;
-	con->out_kvec_left++;
-	con->out_kvec_bytes += auth_len;
-
+	if (auth_len) {
+		con->out_kvec[con->out_kvec_left].iov_base = auth_buf;
+		con->out_kvec[con->out_kvec_left].iov_len = auth_len;
+		con->out_kvec_left++;
+		con->out_kvec_bytes += auth_len;
+	}
 	return 0;
 }