Windows: fix RDR detection of ambiguous directory entries

Windows: fix RDR detection of ambiguous directory entries

The redirector is supposed to reject access to file objects if there
is no case exact match and multiple entries match in a case insensitive
comparison.  The check was only present in the AFSLocateNameEntry()
function and not elsewhere.

Fix the AFSLocateNameEntry() call and addd the missing checks.

Change-Id: I15aba954179fa85e28b348989779bc05122c0037
Reviewed-on: http://gerrit.openafs.org/11929
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>