Windows: afsio reduce library link list

When linking afsio many of the libraries specified in the EXELIB3
list were unnecessary.  The only lib in the list that is required
is libcmd.lib.  Rename EXELIB3 to LIBCMD and prune the rest.

Change-Id: I87bf0583f312d7b3dadc5581c08fedaa6b754c77
Reviewed-on: http://gerrit.openafs.org/9301
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>