logfs: Free areas before calling generic_shutdown_super()

Or hit an assertion in map_invalidatepage() instead.

Signed-off-by: Joern Engel <joern@logfs.org>
diff --git a/fs/logfs/super.c b/fs/logfs/super.c
index f9b7a30..c9ee7f5 100644
--- a/fs/logfs/super.c
+++ b/fs/logfs/super.c
@@ -486,6 +486,7 @@
 	/* Alias entries slow down mount, so evict as many as possible */
 	sync_filesystem(sb);
 	logfs_write_anchor(sb);
+	free_areas(sb);
 
 	/*
 	 * From this point on alias entries are simply dropped - and any