GFS2: flush the log and all pages for jdata as we do for WB_SYNC_ALL

In function gfs2_write_inode, starting with patch a9185b41, we
only flush the log and call filemap_fdatawait if we're passed in a
wbc sync_mode of WB_SYNC_ALL. We also need to do these things if
we're evicting a jdata inode, because we might have jdata pages
still attached to bufdata descriptors that need to be revoked, but
by the time it gets to evict() it's too late to start a new
transaction. This patch changes it to treat jdata inodes as if
WB_SYNC_ALL had been specified.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Acked-by: Abhijith Das <adas@redhat.com>