Ceph

This happened on master + an rbd fix when running 'rbd snap purge blah', when the blah image had > 200 snapshots. Core and binary are in vit:~joshd/bug_1986.

(gdb) bt
#0  0x00007f720a0dde2b in raise (sig=<value optimized out>) at ../nptl/sysdeps/unix/sysv/linux/pt-raise.c:41
#1  0x0000000000458dc8 in reraise_fatal (signum=20606) at global/signal_handler.cc:59
#2  0x00000000004592f1 in handle_fatal_signal (signum=<value optimized out>) at global/signal_handler.cc:109
#3  <signal handler called>
#4  Objecter::handle_osd_op_reply (this=0x126aa80, m=<value optimized out>) at osdc/Objecter.cc:1182
#5  0x00007f720a373f9c in librados::RadosClient::_dispatch (this=0x1268b90, m=0x127d230) at librados.cc:1069
#6  0x00007f720a374023 in librados::RadosClient::ms_dispatch (this=0x1268b90, m=0x127d230) at librados.cc:1039
#7  0x00000000004b6b73 in Messenger::ms_deliver_dispatch (this=0x1269c00) at msg/Messenger.h:102
#8  SimpleMessenger::dispatch_entry (this=0x1269c00) at msg/SimpleMessenger.cc:364
#9  0x000000000048f0ac in SimpleMessenger::DispatchThread::entry() ()
#10 0x00007f720a0d58ba in start_thread (arg=<value optimized out>) at pthread_create.c:300
#11 0x00007f72089c302d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#12 0x0000000000000000 in ?? ()
(gdb) frame 4
#4  Objecter::handle_osd_op_reply (this=0x126aa80, m=<value optimized out>) at osdc/Objecter.cc:1182
1182        if (*p)