Linux: change protobuf default option to allow building

sync/protocol/device_info_specifics.proto

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Sync protocol datatype extension for nigori keys.
 
 // Update proto_value_conversions{.h,.cc,_unittest.cc} if you change
 // any fields in this file.
 
 syntax = "proto2";
 
-option optimize_for = LITE_RUNTIME;
-option retain_unknown_fields = true;
-
 package sync_pb;
 
 import "sync_enums.proto";
 
 // Information about a device that is running a sync-enabled Chrome browser.  We
 // are mapping the per-client cache guid to more specific information about the
 // device.
 message DeviceInfoSpecifics {
   // The cache_guid created to identify a sync client on this device.
   optional string cache_guid = 1;
 
   // A non-unique but human readable name to describe this client.
   optional string client_name = 2;
 
   // The platform of the device.
   optional SyncEnums.DeviceType device_type = 3;
 
   // The UserAgent used when contacting the Chrome Sync server.
   optional string sync_user_agent = 4;
 
   // The Chrome instance's version.  Updated (if necessary) on every startup.
   optional string chrome_version = 5;
 }