Windows: cm_GiveUpAllCallBacksAllServersMulti()

Windows: cm_GiveUpAllCallBacksAllServersMulti()

Implement a multi_RXAFS_GiveUpAllCallBacks version of
cm_GiveUpAllCallBacksAllServers() and use it in place of
the non-multi version.

Reviewed-on: http://gerrit.openafs.org/3648
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
(cherry picked from commit 5fe04739e0407079a0439f28c6aaaa86d5399e71)

Change-Id: I99660917d9f658cb95be6655aa9fb30cdf73b164
Reviewed-on: http://gerrit.openafs.org/3865
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>