tune2fs: warn if the filesystem journal is dirty

tune2fs: warn if the filesystem journal is dirty

Running tune2fs on a filesystem with an unrecovered journal can
cause the tune2fs settings changes in the superblock to be reverted
when the journal is replayed if it contains an uncommitted copy of
the superblock.  Print a warning if this is detected so that the
user isn't surprised if it happens.

Signed-off-by: Jim Garlick <garlick@llnl.gov>
Updated message printed to include steps to replay journal.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>