[luci-config] Use F2 instance class on backend
[luci-config] Use F2 instance class on backend

Bump luci-config instance class to F2 to resolve OOMs.

R=9f116ddb1b24f6fc1916a676eb17161b6c07dfc1@chromium.org

Change-Id: I920e8dea1a549405f14f1b3888d50093b8e90c84
Reviewed-on: https://chromium-review.googlesource.com/1142138
Reviewed-by: Vadim Shtayura <9f116ddb1b24f6fc1916a676eb17161b6c07dfc1@chromium.org>
Commit-Queue: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>

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