Set default to v4

Seems like we didn't fix the problem with the last patch. This should
finally fix it.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>

lib/config/default.js

@@ -104,7 +104,8 @@ module.exports = {
     baseURL: undefined,
     clientID: undefined,
     clientSecret: undefined,
-    scope: undefined
+    scope: undefined,
+    version: 'v4'
   },
   mattermost: {
     baseURL: undefined,