Fileserver: Add the /vicepXX/NeverAttach flag to skip mounting a partition

Fileserver: Add the /vicepXX/NeverAttach flag to skip mounting a partition

FIXES 130561

LICENSE MIT

Reviewed-on: http://gerrit.openafs.org/7108
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Jason Edgecombe <jason@rampaginggeek.com>
(cherry picked from commit 35becabed870d4bfe49abaa499d99a3ffb0a2d31)

Change-Id: If14e0145404dcb81fb5d2184c0991fa3ca64a1df
Reviewed-on: http://gerrit.openafs.org/9470
Tested-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Tested-by: Stephan Wiesand <stephan.wiesand@desy.de>