Btrfs: check-int: don't complain about balanced blocks

The xfstest btrfs/014 which tests the balance operation caused that the
check_int module complained that known blocks changed their physical
location. Since this is not an error in this case, only print such
message if the verbose mode was enabled.

Reported-by: Wang Shilong <wangshilong1991@gmail.com>
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Tested-by: Wang Shilong <wangshilong1991@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>