GFS2: Only set PageChecked for jdata pages

Before this patch, GFS2 was setting the PageChecked flag for ordered
write pages. This is unnecessary. The ext3 file system only does it
for jdata, and it's only used in jdata circumstances. It only muddies
the already murky waters of writing pages in the aops.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>