CHROMIUM: don't clobber PATH for socket event

The upstream fixes missed one place.

BUG=chromium:616778
TEST=test 'start on socket ...' with using SOCKET_PATH= instead of PATH=

Reviewed-on: https://chromium-review.googlesource.com/343271
Change-Id: I27be02af653e6bcaf1c2cf08c79ae6a1d8c5492b
1 file changed