Check for unstable ulog in ulog_get_entries

Check for unstable ulog in ulog_get_entries

If a process terminates in the middle of a logged database update, it
will release its lock and leave the ulog in the KDB_UNSTABLE state.
kadmind should notice this when it calls ulog_get_entries, but right
now it only checks for the KDB_CORRUPT state (which is never set any
more) and does not recover.  Check for any state other than KDB_STABLE
and recover by resetting the ulog and forcing full resyncs to slaves.

ticket: 7853 (new)
target_version: 1.12.2
tags: pullup