dir-locals: update emacs indent

.dir-locals.el

@@ -1,7 +1,12 @@
 ((c-mode . ((c-file-style . "linux")
-            (indent-tabs-mode . t)
+            (indent-tabs-mode . nil)
             (show-trailing-whitespace . t)
             (c-basic-offset . 4)
             (tab-width . 4)
             ))
+ (vala-mode . ((indent-tabs-mode . nil)
+               (show-trailing-whitespace . t)
+               (c-basic-offset . 4)
+               (tab-width . 4)
+               ))
  )