resize2fs: relax requirements for -P output a bit

resize2fs: relax requirements for -P output a bit

Requiring an immediate pre-fsck before printing a minimum
resize size seems a bit draconian; if the fs isn't clean or marked
with error, then certainly, but for an informational minimum
size, I don't think we need to require a fsck since last mount.

I had simply copied the checks from the actual resize path,
previously.

Installers use this option (-P) to gather minimum resize info,
and requiring an actual fsck before use just seems to go too far.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>