Windows: TRANS2_FIND_FIRST2 for _._AFS_IOCTL_._

Windows: TRANS2_FIND_FIRST2 for _._AFS_IOCTL_._

smb_T2SearchDirSingle() must not fail directory search requests
for the _._AFS_IOCTL_._ file.  Although this file does not actually
exist, it is successfully processed by CreateFile operations.
Therefore, an explicit search for it should return a valid answer.

Change-Id: I9df3443f0bdf0dd05caac74f4de3a0cc64d26800
Reviewed-on: http://gerrit.openafs.org/4884
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>