ubik: Initialise global version lock before use

ubik: Initialise global version lock before use

Commit e4ac552ab79be21d90397079eaf6be7050497752 introduced a global
version lock to ubik, but doesn't initialise this lock before make use
of it. On platforms which require that pthread mutexes are initialsed,
this causes an assertion failure.

Initialise this lock at the same time as we MUTEX_INIT all of our other
locks.

Change-Id: Ib5ef75d443101a823738fba55c0760cb1848dbcf
Reviewed-on: http://gerrit.openafs.org/4780
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Marc Dionne <marc.c.dionne@gmail.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>