far-progs: adapt tests to new Btrfs-progs mkfs and send options

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
diff --git a/refgen.pl b/refgen.pl
index add06d4..6c0ba00 100755
--- a/refgen.pl
+++ b/refgen.pl
@@ -115,7 +115,7 @@
 	system("zfs create -o mountpoint=$path $zfs_name");
 	die "zfs create $zfs_name failed\n" if ($?);
 } else {
-	system("mkfs.btrfs -L refgen-fs $btrfs_dev");
+	system("mkfs.btrfs -fL refgen-fs $btrfs_dev");
 	die "mkfs.btrfs $btrfs_dev failed\n" if ($?);
 	system("mount -o noatime,inode_cache $btrfs_dev $path");
 	die "mount $btrfs_dev failed\n" if ($?);
diff --git a/test.pl b/test.pl
index a577920..ad75b41 100755
--- a/test.pl
+++ b/test.pl
@@ -473,7 +473,7 @@
 			do_local("umount", $dst_mnt);
 			do_remote("umount", $src_mnt);
 		}
-		do_local("mkfs.btrfs", "-L", "fits", $dst_dev);
+		do_local("mkfs.btrfs", "-fL", "fits", $dst_dev);
 		do_local("mount", "-o", "noatime", $dst_dev, $dst_mnt);
 
 		do_remote($p_perl, "-", "-p", $src_mnt, $src_type_opt, $src_dev,