GeniePlus: fix Guzzle error handling.

[demiankatz]

When attempting a GeniePlus reharvest after upgrading to the latest RecordManager, I discovered that OAuth renewals were not working correctly because Laminas HTTP error handling differs from Guzzle HTTP error handling. This PR fixes the problem -- it may be worth reviewing whether any other drivers have similar problems.

TODO

• Run local test to confirm refactored code still works before merging

[EreMaijala]

I think it would be cleaner to set http_errors to false in $this->httOptions. I did a similar change to SierraApi quite recently, but didn't realize at the time that GeniePlus was similarly affected.

[demiankatz]

Thanks, @EreMaijala, I agree! My first pass on this was an attempt to use the http_errors setting, but I think I was putting it in the wrong place and it wasn't working. I have revised the code based on your SierraRest example, and I think this should work. I'm running a test now but will have to wait at least 20 minutes to be sure it works. I'll request a re-review now, but please do not merge this until I have confirmed that it actually works on my end!

[demiankatz]

Confirmed: the revised code works the same as the original code.