Bugfix in configuration using google-services.json

Author: BlooJeans

android/src/main/java/io/fullstack/firestack/FirestackModule.java

@@ -66,7 +66,7 @@ public String setKeyOrDefault(
           final String val = params.getString(key);
           Log.d(TAG, "Setting " + key + " from params to: " + val);
           return val;
-        } else if (defaultValue != null && defaultValue != "") {
+        } else if (defaultValue != null && !defaultValue.equals("")) {
           Log.d(TAG, "Setting " + key + " from params to: " + defaultValue);
           return defaultValue;
         } else {