Add more temporary #ifdef to mtpd, so it can build with both libchrome-180609 and with Chromium r205050+.

BUG=none
TEST=emerge mtpd on ChromeOS, ninja -C out/Debug mtpd on Linux.

Change-Id: Ib6e6ec01e4e62042a3edf7e5d78affba7db43279
Reviewed-on: https://gerrit.chromium.org/gerrit/59508
Tested-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
4 files changed