Don't swallow errors

[dogmatic69]

Just spent a good few hours debugging an issue in a request which was reported as:

Error when contacting https://....

but was actually some AsyncIO error due to blocking calls within a async loop.

This should only catch underlying HTTP errors

https://github.com/MikeWooster/api-client/blob/522700a80405b9523d0613ff96162241a2abd72e/apiclient/request_strategies.py#L99