Trap an error on Preferences (OpenUserJS#1371)

* Prevents server trip until DB can be cleansed

Applies to OpenUserJS#1369 

Auto-merge

controllers/user.js

@@ -890,7 +890,7 @@ exports.userEditPreferencesPage = function (aReq, aRes, aNext) {
           return aStrategy.display;
         });
 
-        options.defaultStrategy = strategies[defaultStrategy].name;
+        options.defaultStrategy = strategies[defaultStrategy] ? strategies[defaultStrategy].name : null;
         options.defaultStrat = defaultStrategy;
         options.haveOtherStrategies = options.usedStrategies.length > 0;