Use unsigned IP addresses in bu*

Use unsigned IP addresses in bu*

Use unsigned IP addresss in bubasics, bucoord, and butc code. This
alters the public tcdata.p.h, but stays away from wire RPCs or
variables used directly with those RPCs.

Change-Id: Ica96172399cafbc2c347f725a966cf1db7ff1128
Reviewed-on: http://gerrit.openafs.org/2255
Tested-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>