Temporarily stop building Node 7 on Windows

ofrobots · web-flow · commit 75b08e90cff2 · 2016-12-14T17:15:20.000-08:00
grpc is not supported with Node 7 on Windows at the moment. Stop building in that config for now. See googleapis#190 for more context.
diff --git a/appveyor.yml b/appveyor.yml
@@ -4,7 +4,6 @@ environment:
   # node.js
   - nodejs_version: "4"
   - nodejs_version: "6"
-  - nodejs_version: "7"
 
 # Install scripts. (runs after repo cloning)
 install:
