gce_backend_service module expects healthchecks to be an array of string. The previous example incorrectly mentioned healthchecks as an array of objects each containing a `name` key.
* The canonical location of BOOLEANS has moved. Switch imports to use that.
* clean up argument_spec use of booleans.
* Clean up imports to not use wildcards
* Remove usage of get_exception
* GCP: backend service module
* GCP: rework param-checking code. Fixed a couple of bugs and changed to ValueError instead of custom tuple.
* GCP: fixed commit, spelled out Google Cloud for clarity in module description.
Vibhav Sinha
Dag Wieers
Toshio Kuratomi
Andrea Tartaglia
Tom Melendez