btrfs: use $FILEFRAG_PROG instead of filefrag

$FILEFRAG_PROG has been defined in common/config, so
we could apply it.

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/btrfs/004

@@ -53,7 +53,7 @@ _require_scratch
 _require_no_large_scratch_dev
 _require_btrfs_command inspect-internal logical-resolve
 _require_btrfs_command inspect-internal inode-resolve
-_require_command "/usr/sbin/filefrag" filefrag
+_require_command "$FILEFRAG_PROG" filefrag
 
 rm -f $seqres.full
 
@@ -82,7 +82,7 @@ _filter_extents()
 
 _check_file_extents()
 {
-	cmd="filefrag -v $1"
+	cmd="$FILEFRAG_PROG -v $1"
 	echo "# $cmd" >> $seqres.full
 	out=`$cmd | _filter_extents`
 	if [ -z "$out" ]; then

tests/btrfs/079

@@ -60,7 +60,7 @@ _supported_os Linux
 _require_scratch
 # Since xfs_io's fiemap always use SYNC flag and can't be unset,
 # we must use filefrag to call fiemap without SYNC flag.
-_require_command "/usr/sbin/filefrag" filefrag
+_require_command "$FILEFRAG_PROG" filefrag
 _require_xfs_io_command "falloc"
 
 filesize=$((10 * 1024 * 1024 * 1024)) #10G size
@@ -95,7 +95,7 @@ _filter_error() {
 fiemap_work() {
 	filename=$1
 	while true; do
-		filefrag $filename 2> $tmp.output 1> /dev/null
+		$FILEFRAG_PROG $filename 2> $tmp.output 1> /dev/null
 		ret=$?
 		err=`cat $tmp.output | _filter_error`
 		if [ $ret -ne 0 -o -n "$err" ]; then