e2fsck: fix last mount/write time when e2fsck is forced

e2fsck: fix last mount/write time when e2fsck is forced

With commit c52d930f e2fsck is no longer able to fix bad last
mount/write time by default because it is conditioned on s_checkinterval
not being zero, which it is by default.

One place where it matters is when other e2fsprogs tools require to run
full file system check before a certain operation. If the last mount
time is for any reason in future, it will not allow it to run even if
full e2fsck is ran.

Fix it by checking the last mount/write time when the e2fsck is forced,
except for the case where we know the system clock is broken.

[ Reworked the conditionals so error messages claiming that the last
  write/mount time were corrupted wouldn't be always printed when the
  e2fsck was run with the -f option, thus causing 299 out of 372
  regression tests to fail.  -- TYT ]

Fixes: c52d930f ("e2fsck: don't check for future superblock times if checkinterval == 0")
Reported-by: Dusty Mabe <dustymabe@redhat.com>
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>