Delete gke.py.
Delete gke.py.

It is unused.

R=40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org
BUG=1048479

Change-Id: Ib92de6b69c930d246f501f63e34e4ed4b1a75560
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/2067407
Reviewed-by: Robbie Iannucci <40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org>
Commit-Queue: Vadim Shtayura <9f116ddb1b24f6fc1916a676eb17161b6c07dfc1@chromium.org>

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py