ubik: locking in recovery.c

ubik: locking in recovery.c

Locking changes in recovery.c:
- In urecovery_Initialize, hold the DB lock over ReplayLog
and InitializeDB
- Hold the DB lock over larger portions of urecovery_interact.
Some values which should be protected were examined and modified
without holding any locks.
- In the early part of urecovery_interact, only take the DB lock
when it's really needed, now that some values are protected by other
locks.
- DoProbe is now called without the DB lock, so it doesn't need to
drop and re-aquire it.

Change-Id: I1899b672687f0ab0eb59c74ff802750cdc377ae6
Reviewed-on: http://gerrit.openafs.org/4524
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>