Windows: Support arbitrary callback ports

Windows: Support arbitrary callback ports

Reconfigure the advanced firewall to support callback ports
other than port 7001.

This changes the semantics of the afsicf api.  AFS_PORTSET_SERVER is now
zero.  Any other value is treated as a callback port.

Change-Id: I4df421cc0ceb4dca94a6b5e81990115a4ce0334e
Reviewed-on: http://gerrit.openafs.org/10776
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>