e2fsck: fix last mount time and last write time in preen mode

e2fsck: fix last mount time and last write time in preen mode

Fixing last mount time and last write time is safe - there's no risk of
loosing any important information or making corruption significantly
worse even if we get it wrong. So let's just fix these times in preen
mode. This allows initrd to automatically check and mount root
filesystem in case system clock is wrong without having to manually set
broken_system_clock variable (openSUSE uses broken_system_clock by default
to avoid these problems during boot but this disables time-based checks
even on systems where clock is fine so that's not ideal either).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>