The rx calls will take locks when built in pthreaded mode, and must go
after rx_Init(). Some other setup would benefit from using time-domain
locking and should run before we go multithreaded.
In particular, initialize bozo_confdir while single-threaded, as it is
otherwise protected by the afsconf internal locking. While here, pass
NULL to afsconf_SetCellInfo -- bozo_confdir would always be NULL there,
anyway.
Change a couple globals into local variables in main; they are just
used to defer setup after argument parsing.
ReadBozoFile will create worker threads to monitor child processes,
so it cannot move up too far.