update backend: ensure coding-ide-home exist

tanhe123 · tanhe123 · commit 9ef2779abbf0 · 2016-09-22T15:52:49.000+08:00
diff --git a/backend b/backend
@@ -1 +1 @@
-Subproject commit e7697091bd639560673101b55e32ed37c2cb5de9
+Subproject commit b76916ce23c1f2f050d4cfd9f120094f97fb71bc
