mds/journal: make used_preallocated_ino crash more graceful

mds/journal: make used_preallocated_ino crash more graceful

failure while removing used_preallocated_ino from session's prealloc_inos
set leads to backtrace pointing to interval_set:

interval_set<inodeno_t, std::map>::erase(inodeno_t, inodeno_t, std::function<bool (inodeno_t, inodeno_t)>)
EMetaBlob::replay(MDSRank*, LogSegment*, MDPeerUpdate*)
EUpdate::replay(MDSRank*)
MDLog::_replay_thread()
MDLog::ReplayThread::entry()

which is cumbersome to debug, while the actual root cause is still a WIP, make the crash more graceful
so that it helps while debugging.

Signed-off-by: Dhairya Parmar <dparmar@redhat.com>