Windows: cm_UpdateIFInfo consolidate syscfg_GetIFInfo calls

Windows: cm_UpdateIFInfo consolidate syscfg_GetIFInfo calls

Add a new function cm_UpdateIFInfo() that consolidates all of the
syscfg_GetIFInfo() call functionality into a single rountine.  Replace
all of the existing call sites.

It is safe to call cm_UpdateIFInfo() without holding cm_syscfgLock
during afsd initialization because no other threads have been created.

Change-Id: Ifd4ca4f4f698014852a26d2c95a523c3b2cc851f
Reviewed-on: http://gerrit.openafs.org/11443
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>