tune2fs: move the journal recovery before we try to modify the superblock

tune2fs: move the journal recovery before we try to modify the superblock

Also change the t_replay_and_set test so that we do something more
innocuous, such as setting the file system label, instead of something
much more dangerous such as removing metadata_csum feature (which
requires rewriting the metadat checksums, and this will fail
catastrophically after the test corrupts the inode bitmaps and we
perform the journal replay correctly).

Reported-by: NeilBrown <neilb@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>