fstests: make xfs/006 generic

xfs/006 has no requirements that are specific to XFS, so make it generic
and other filesystems could get some coverage too.

Along with the movement, I also added a test that removes all created
dirs, as that's how the original bug was found.

Signed-off-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

tests/xfs/006

@@ -1,63 +0,0 @@
-#! /bin/bash
-# FS QA Test No. 006
-#
-# Test that directory hash entries are place in the correct order.
-# commit f5ea110 ("xfs: add CRCs to dir2/da node blocks") left the
-# directory with incorrect hash ordering.
-#
-#-----------------------------------------------------------------------
-# Copyright (c) 2014 Hannes Frederic Sowa.  All Rights Reserved.
-#
-# This program is free software; you can redistribute it and/or
-# modify it under the terms of the GNU General Public License as
-# published by the Free Software Foundation.
-#
-# This program is distributed in the hope that it would be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write the Free Software Foundation,
-# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
-#-----------------------------------------------------------------------
-#
-
-seq=`basename $0`
-seqres=$RESULT_DIR/$seq
-echo "QA output created by $seq"
-
-here=`pwd`
-tmp=/tmp/$$
-status=1	# failure is the default!
-trap "_cleanup; exit \$status" 0 1 2 3 15
-
-_cleanup()
-{
-    cd /
-    rm -f $tmp.*
-}
-
-# get standard environment, filters and checks
-. ./common/rc
-. ./common/filter
-. ./common/repair
-
-# real QA test starts here
-
-_supported_fs xfs
-_supported_os Linux
-_require_scratch
-
-_scratch_mkfs_xfs | _filter_mkfs 2>$tmp.mkfs
-_scratch_mount | _filter_scratch
-
-mkdir $SCRATCH_MNT/x
-$here/src/dirhash_collide -d -n 10000 $SCRATCH_MNT/x
-_scratch_unmount 2>&1 | _filter_scratch
-
-_scratch_xfs_repair 2>&1 | _filter_repair
-
-# success, all done
-status=0
-exit