[luci-notify] Log build id in pubsub handler
[luci-notify] Log build id in pubsub handler

Log id of the build being processed in a pubsub handler.

Bug: 848781
Change-Id: Ie7d69659debd3b41edcaf9236a735253bef1dedd
Reviewed-on: https://chromium-review.googlesource.com/1082957
Reviewed-by: Mike Nichols <a217dfaf08c8b0badf42d1d2b157a80c57e389bc@chromium.org>
Commit-Queue: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go