reiserfs: mark the superblock as dirty a bit later

reiserfs: mark the superblock as dirty a bit later

The 'journal_mark_dirty()' function currently first marks the superblock as
dirty by setting 's_dirt' to 1, then does various sanity checks and returns,
then actuall does all the magic with the journal.

This is not an ideal order, though. It makes more sense to first do all the
checks, then do all the internal stuff, and at the end notify the VFS that the
superblock is now dirty.

This patch moves the 's_dirt = 1' assignment from the very beginning of this
function to the very end.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>