Config: Cause a fatal() when a parameter without a default value isn't set(FS #315).

src/python/m5/SimObject.py

@@ -748,7 +748,8 @@ class SimObject(object):
         for param in param_names:
             value = self._values.get(param)
             if value is None:
-                continue
+                m5.fatal("%s.%s without default or user set value" \
+                        % (self.path(), param))
 
             value = value.getValue()
             if isinstance(self._params[param], VectorParamDesc):