chromeperf dashboard: fix problem with runtime import path manipulation
chromeperf dashboard: fix problem with runtime import path manipulation

The following should all work now:

`export PATH=$PATH:/usr/lib/google-cloud-sdk`
`export PATH=$PATH:/usr/lib/google-cloud-sdk/`
`export PATH=$PATH:/usr/lib/google-cloud-sdk/bin`
`export PATH=$PATH:/usr/lib/google-cloud-sdk/nonexstientfileworksonlybyaccident`

The first one is the actual directory path, which doesn't work without this change.
The second is equivalent to the first. Third is currently in use by some users,
but only works by accident. That `bin` part at the end is thrown away,
and could actually be anything at all (fourth example).

Change-Id: Icd55e4f579f4f8ef15989c89a0e9c8a91a30cf68
Reviewed-on: https://chromium-review.googlesource.com/c/catapult/+/3023015
Reviewed-by: Ryan Heise <50ee0a56d43e9e15503d071e9ceb1a6059353025@google.com>
Commit-Queue: Sean McCullough <7caa448b00260c603c5227306703b63f5f75ff01@google.com>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult