Drop 2gb-rootfs disk layout override for amd64-generic-chromium-pfq

After https://chromium-review.googlesource.com/c/486248/,
image_to_vm.sh gets the disk layout to use from the bot config. It
turns out that amd64-generic-chromium-pfq had an incompatible
override. 2gb-rootfs doesn't have a large enough stable partition to
run VMTests. Drop the override so it picks up the default
2gb-rootfs-updatable, which has sufficient stateful spcae.

BUG=chromium:697967
TEST=No more 'No space left on device' errors in VMTest step on amd64-generic-chromium-pfq

Change-Id: I940e62073009148942c941485c9d58b2946af170
Reviewed-on: https://chromium-review.googlesource.com/490288
Tested-by: Mattias Nissler <mnissler@chromium.org>
Trybot-Ready: Mattias Nissler <mnissler@chromium.org>
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
2 files changed