Remove brace initialization for gcc-4.4 compatibility

src/compiler/objective_c_generator.cc

@@ -101,11 +101,13 @@ void PrintAdvancedSignature(Printer *printer,
 }
 
 inline map<string, string> GetMethodVars(const MethodDescriptor *method) {
-  return {{ "method_name", method->name() },
-          { "request_type", method->input_type()->name() },
-          { "response_type", method->output_type()->name() },
-          { "request_class", ClassName(method->input_type()) },
-          { "response_class", ClassName(method->output_type()) }};
+  map<string,string> res;
+  res["method_name"] = method->name();
+  res["request_type"] = method->input_type()->name();
+  res["response_type"] = method->output_type()->name();
+  res["request_class"] = ClassName(method->input_type());
+  res["response_class"] = ClassName(method->output_type());
+  return res;
 }
 
 void PrintMethodDeclarations(Printer *printer,