ctdbd_conn: Fix ctdbd_connection_destructor

ctdbd_conn: Fix ctdbd_connection_destructor

clang had complained with

../source3/lib/ctdbd_conn.c:1784:34: warning: variable 'send_state' used in loop condition
      not modified in loop body [-Wfor-loop-analysis]
        for (send_state = c->send_list; send_state != NULL;) {
                                        ^~~~~~~~~~
../source3/lib/ctdbd_conn.c:1791:34: warning: variable 'recv_state' used in loop condition
      not modified in loop body [-Wfor-loop-analysis]
        for (recv_state = c->recv_list; recv_state != NULL;) {
                                        ^~~~~~~~~~

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
Autobuild-User(master): Volker Lendecke <vl@samba.org>
Autobuild-Date(master): Sat Jun 10 03:33:13 CEST 2017 on sn-devel-144