Set new Melange version number to 2-1-20150412.

Change-Id: Ic1a5de481df65e64f463dbc5d2ebaf11754780b8
diff --git a/app/app.yaml.template b/app/app.yaml.template
index e33ce4a..071f71d 100644
--- a/app/app.yaml.template
+++ b/app/app.yaml.template
@@ -15,7 +15,7 @@
 # TODO(proto): uncomment and supply a Google App Engine application instance
 # application: FIXME
 # TODO(release): see the instructions in README about the "version:" field
-version: 2-1-20150401
+version: 2-1-20150412
 runtime: python27
 api_version: 1
 threadsafe: false