Some winbindd cleanups I made trying to fix cr1020:

Some winbindd cleanups I made trying to fix cr1020:

 - move winbindd client handling into accessor functions in
   winbindd_util.c

 - move some winbindd socket routines into accessor functions in
   winbindd_utils.c

(The deadlock situation mentioned in the appliance branch is probably
not applicable since we don't clear the connection cache on SIGHUP.
Perhaps we should?)