Log a warning when a user logs in but doesn't have an email address in the profile controller.

lib/units/auth/oauth2/index.js

@@ -43,6 +43,7 @@ module.exports = function(options) {
         }))
       }
       else {
+        log.warn('Missing email in profile', req.user)
         res.redirect('/auth/oauth/')
       }
     }