librados: close narrow shutdown race

librados: close narrow shutdown race

timer.shutdown() will drop and retake the lock, so set DISCONNECTED first
to avoid a message slipping in and reaching the objecter like so:

INFO:teuthology.task.rados.rados.0.err:osdc/Objecter.cc: In function 'void Objecter::handle_osd_op_reply(MOSDOpReply*)' thread 7f0bc2b1b700 time 2012-03-03 18:35:25.302135
INFO:teuthology.task.rados.rados.0.err:osdc/Objecter.cc: 1151: FAILED assert(initialized)
INFO:teuthology.task.rados.rados.0.err: ceph version 0.43-46-g2e57997 (commit:2e57997894944696fcc737aae9b57e30b6bb5bdc)
INFO:teuthology.task.rados.rados.0.err: 1: (ceph::__ceph_assert_fail(char const*, char const*, int, char const*)+0xb3) [0x7f0bc59bd66f]
INFO:teuthology.task.rados.rados.0.err: 2: (Objecter::handle_osd_op_reply(MOSDOpReply*)+0x82) [0x7f0bc58e885e]
INFO:teuthology.task.rados.rados.0.err: 3: (librados::RadosClient::_dispatch(Message*)+0x66) [0x7f0bc58a2674]
INFO:teuthology.task.rados.rados.0.err: 4: (librados::RadosClient::ms_dispatch(Message*)+0x130) [0x7f0bc58a246e]
INFO:teuthology.task.rados.rados.0.err: 5: (Messenger::ms_deliver_dispatch(Message*)+0x8b) [0x7f0bc5a4e859]
INFO:teuthology.task.rados.rados.0.err: 6: (SimpleMessenger::dispatch_entry()+0x7c2) [0x7f0bc5a377fc]
INFO:teuthology.task.rados.rados.0.err: 7: (SimpleMessenger::DispatchThread::entry()+0x2c) [0x7f0bc58b5512]
INFO:teuthology.task.rados.rados.0.err: 8: (Thread::_entry_func(void*)+0x23) [0x7f0bc5ac4c75]
INFO:teuthology.task.rados.rados.0.err: 9: (()+0x7971) [0x7f0bc5110971]
INFO:teuthology.task.rados.rados.0.err: 10: (clone()+0x6d) [0x7f0bc495092d]

Fixes: #2135
Signed-off-by: Sage Weil <sage@newdream.net>
Reviewed-by: Josh Durgin <josh.durgin@dreamhost.com>