Make site_linux_router work with hostapd 2.1

The newer version of hostapd does not include command line flags to
write out a pid file.

BUG=chromium:365816
TEST=network_WiFi_SimpleConnect.wifi_checkWPA_TKIP passes with the older
hostapd we use today, as well as hostapd 2.1.

Change-Id: Ifdad0199d3c3b7d2451909a102c9a200041a6e3e
Reviewed-on: https://chromium-review.googlesource.com/200260
Tested-by: Christopher Wiley <wiley@chromium.org>
Reviewed-by: Peter Qiu <zqiu@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Commit-Queue: Christopher Wiley <wiley@chromium.org>
1 file changed