Fix deadlock in find_queuebyname().  Locking allques_mutex is required
for the hash table lookup, not the locking of the specific queue.  If
queue Q is locked by thread B and allques_mutex by thread A in
find_queuebyname(), when thread A attempts to lock queue Q, it will
block waiting for thread B's lock.  If thread B then tries to lock
allques_mutex, the two deadlock.

Unlock allques_mutex first, then lock the queue, to prevent this
situation.
Since find_queuebyname() is now at the start of the loop, and it
handles locking the queue for us, remove the mutex_mgr object.
Log routing of jobs.  Watching for memory corruption of queue pointers.