Windows: Remove unused cleanup flag

Windows: Remove unused cleanup flag

In AFSOpenTargetDirectory the flag bRemoveShare was initialized
FALSE and never set TRUE.  In teardown after failure some code
did listen to the flag, but the operation (IoRemoveShareAccess)
was not protected by the FCB mainlock which it should have been.

Rather than get the locking correct, just remove the flag entirely.

Change-Id: I097f15bb0903f3c0889b62427d2169cf84aa04a0
Reviewed-on: http://gerrit.openafs.org/5649
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>