sync scala-backend to remove exhaustivity check warning

liufengyun · liufengyun · commit f5e31d6184cc · 2017-06-07T22:37:57.000+02:00
diff --git a/scala-backend b/scala-backend
@@ -1 +1 @@
-Subproject commit 253ae6c0155a553bef4b1a312e25fc5f18f4c5e4
+Subproject commit fd40234ba42430682c1c4d3456ea8bc861537734
