components: Do not double-throw on deadline
components: Do not double-throw on deadline

If an handler fails due to DeadlineExceededError, it is important to
return as fast as possible. Querying for memory usage is a RPC (!) so it
should be avoided in this case.

R=5de1a387cc854ff3d04fab3d66d4e77a58511771@chromium.org

Bug: 961832
Change-Id: I9856227eed28c255718d4ef03d5438a2267538cf
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/1647211
Reviewed-by: Jao-ke Chin-Lee <5de1a387cc854ff3d04fab3d66d4e77a58511771@chromium.org>
Commit-Queue: Marc-Antoine Ruel <d2bf0fc09b08f7b0888b3ddab32b3e89c7122c8b@chromium.org>

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