UBIFS: increment commit number earlier

Increment the commit number at the beginnig of the commit, instead
of doing this after the commit. This is needed for further
optimizations.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/orphan.c b/fs/ubifs/orphan.c
index 3afeb92..02d3462 100644
--- a/fs/ubifs/orphan.c
+++ b/fs/ubifs/orphan.c
@@ -310,10 +310,10 @@
 	c->cmt_orphans -= cnt;
 	spin_unlock(&c->orphan_lock);
 	if (c->cmt_orphans)
-		orph->cmt_no = cpu_to_le64(c->cmt_no + 1);
+		orph->cmt_no = cpu_to_le64(c->cmt_no);
 	else
 		/* Mark the last node of the commit */
-		orph->cmt_no = cpu_to_le64((c->cmt_no + 1) | (1ULL << 63));
+		orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
 	ubifs_assert(c->ohead_offs + len <= c->leb_size);
 	ubifs_assert(c->ohead_lnum >= c->orph_first);
 	ubifs_assert(c->ohead_lnum <= c->orph_last);