Windows: Apply cm_GetVolServerList() to cm_ConnFromVolume()

Windows: Apply cm_GetVolServerList() to cm_ConnFromVolume()

Use cm_GetVolServerList() in cm_ConnFromVolume() to ensure an
error is returned instead of dereferencing a NULL pointer if
the serverRef list for the requested volume cannot be obtained.

Change-Id: I265b7e8b64fcf6b4444c7d504e5109d67fa48089
Reviewed-on: http://gerrit.openafs.org/7724
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>