[gnome-build-meta/juerg/strip-variables] sdk/vala.bst: Use git_tag source plugin

[Jürg Billeter <juergbi src gnome org>]

commit f98f05bc28af919f37be6bf2cb0d9193e2fe495e
Author: Jürg Billeter <j bitron ch>
Date:   Sat Feb 9 19:03:37 2019 +0100

    sdk/vala.bst: Use git_tag source plugin
    
    This fixes build with BuildStream master.

 elements/sdk/vala.bst | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/elements/sdk/vala.bst b/elements/sdk/vala.bst
index 666965ac..0fc89335 100644
--- a/elements/sdk/vala.bst
+++ b/elements/sdk/vala.bst
@@ -1,8 +1,9 @@
 kind: autotools
 sources:
-- kind: git
+- kind: git_tag
   url: gitlab_gnome_org:GNOME/vala
   track: master
+  track-tags: True
 depends:
 - sdk/glib.bst
 - filename: sdk/vala-tarball.bst