UBIFS: ensure orphan area head is initialized

When mounting read-only the orphan area head is
not initialized.  It must be initialized when
remounting read/write, but it was not.  This patch
fixes that.

[Artem: sorry, added comment tweaking noise]
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index f175435..9999ff0 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1604,6 +1604,7 @@
 int ubifs_orphan_start_commit(struct ubifs_info *c);
 int ubifs_orphan_end_commit(struct ubifs_info *c);
 int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only);
+int ubifs_clear_orphans(struct ubifs_info *c);
 
 /* lpt.c */
 int ubifs_calc_lpt_geom(struct ubifs_info *c);