Revert "xfstests 311: test fsync with dm flakey V3"

This reverts commit 2ca254dfdd.
Patch will be resubmitted

common/rc

@@ -57,13 +57,6 @@ dd()
    fi
 }
 
-# Prints the md5 checksum of a given file
-_md5_checksum()
-{
-	md5sum $1 | cut -d ' ' -f1
-}
-
-
 # ls -l w/ selinux sometimes puts a dot at the end:
 # -rwxrw-r--. id1 id2 file1
 
@@ -1057,22 +1050,6 @@ _require_command()
     [ -n "$1" -a -x "$1" ] || _notrun "$_cmd utility required, skipped this test"
 }
 
-# this test requires the device mapper flakey target
-#
-_require_dm_flakey()
-{
-    _require_command $DMSETUP_PROG
-
-    modprobe dm-flakey >/dev/null 2>&1
-    $DMSETUP_PROG targets | grep flakey >/dev/null 2>&1
-    if [ $? -eq 0 ]
-    then
-	:
-    else
-	_notrun "This test requires dm flakey support"
-    fi
-}
-
 # this test requires the projid32bit feature to be available in
 # mkfs.xfs
 #