[luci-notify] Do not treat all handleBuild errors as transient
[luci-notify] Do not treat all handleBuild errors as transient

Gitiles returning 404 is not a transient error.

Change-Id: Id40297d49a1d99bdf0718c800cb1a94bf46ce58f
Reviewed-on: https://chromium-review.googlesource.com/1077488
Reviewed-by: Michael Knyszek <4473450dc5c88f06e1fb787f303d7805ec2aee65@google.com>
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