Windows: Prevent MDL leak on Cc*Mdl* failure

If CcMdlRead or CcPrepareMdlWrite fail, check the IoStatus.Information
field to see if any MDL pages have been locked.  If the Information
value is greater than zero, complete the Mdl operation to unlock the
pages.

Change-Id: Icb44e74e25b46c7976f3f418410364a90a723d91
Reviewed-on: http://gerrit.openafs.org/11442
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Peter Scott <pscott@kerneldrivers.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
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>