xfstests: unify apostrophes in output files

With coreutils v8.16 the style of apostrophes changed from `word' to
'word'. This is breaking some tests which use the older form.

This commit introduces function changes the golden output of the
affected tests and introduces a filter for the older style output.

[dchinner: modified to use a global filter in check rather than
per-test filters]
[rjohnston: minor comment change]

Signed-off-by: Tomas Racek <tracek@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Rich Johnston <rjohnston@sgi.com>

check

@@ -485,6 +485,10 @@ do
 		echo " - no qualified output"
 		err=true
 	    else
+
+		# coreutils 8.16+ changed quote formats in error messages from
+		# `foo' to 'foo'. Filter old versions to match the new version.
+		sed -i "s/\`/\'/g" $tmp.out
 		if diff $seq.out $tmp.out >/dev/null 2>&1
 		then
 		    if $err