Windows: \\afs\all is not a server for NP enumeration

Windows: \\afs\all is not a server for NP enumeration

\\afs\all is a special share name that refers to the global root
which in the AFS redirector is actually \\AFS.  However, from the
perspective of the network provider interface \\afs\all is just a
share which refers to a directory.   Do not treat attempts to evaluate
it as if they were the same as evaluating \\AFS.  One is a global
enumeration (\\AFS) and the other is just a hidden share name.

Change-Id: I24af24ec005c729bb1430c55254f2b68689932ed
Reviewed-on: http://gerrit.openafs.org/9750
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Rod Widdowson <rdw@steadingsoftware.com>
Reviewed-by: Peter Scott <pscott@kerneldrivers.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>