This method was still failing for me with a "missing http_code" message. After applying this change, the error message is:
```
msg: Unexpected response: {'value': 'PyCrypto library required for Service Account Authentication.'}
```
I wanted to contribute a rock-solid `unexpected_error_msg` implementation.
In order to simplify the workflow with the GCE modules, it's now
possible to add the parameters and project name as arguments to the
various GCE modules.
The inventory plugin also returns the IP of the host in
`ansible_ssh_host` so that you don't have to specify IPs into the
inventory file.
Some update to the documentation are also added.
Closes#5583.
