makefs: supress mkfs output, but print one line on success

makefs: supress mkfs output, but print one line on success

$ for i in ext2 ext3 ext4 btrfs xfs vfat swap minix; do
  echo $i && wipefs -q -a /var/tmp/test2_img && build/systemd-makefs $i /var/tmp/test2_img
done

ext2
/var/tmp/test2_img successfully formatted as ext2 (label "test2_img", uuid ad584a5b-037b-497a-825d-eaf2ba90da2d)
ext3
/var/tmp/test2_img successfully formatted as ext3 (label "test2_img", uuid 95239fff-55f4-44d5-bae0-11ef75d13166)
ext4
/var/tmp/test2_img successfully formatted as ext4 (label "test2_img", uuid 8c7ea699-05ab-4ce6-8df6-bc20d53dfd29)
btrfs
/var/tmp/test2_img successfully formatted as btrfs (label "test2_img", uuid 860bb061-4d92-4607-8821-a9d00216490e)
xfs
/var/tmp/test2_img successfully formatted as xfs (label "test2_img", uuid f32499ea-7311-47bb-be57-da62e51d33ae)
vfat
mkfs.fat 4.2 (2021-01-31)
/var/tmp/test2_img successfully formatted as vfat (label "TEST2_IMG", uuid d1e4ae63)
swap
mkswap: /var/tmp/test2_img: insecure permissions 0644, fix with: chmod 0600 /var/tmp/test2_img

mkswap: /var/tmp/test2_img contains holes or other unsupported extents.
        This swap file can be rejected by kernel on swap activation!
        Use --verbose for more details.

Setting up swapspace version 1, size = 256 MiB (268431360 bytes)
LABEL=test2_img, UUID=16bc3d8c-98d4-462b-8ff8-338467cde871
/var/tmp/test2_img successfully formatted as swap (no label or uuid specified)
minix
21856 inodes
65535 blocks
Firstdatazone=696 (696)
Zonesize=1024
Maxsize=268966912

/var/tmp/test2_img successfully formatted as minix (no label or uuid specified)