Improve errors verbosity for Java native exceptions

[pilosus]

It seems that changes made in #115 don't handle exceptions well when it's an exception outside of the clj-http exceptional status codes, e.g. when it's a pure Java exceptions like UnknownHostException or something related to connection timeouts. Such exceptions get caught, but the verbosity output messes up with getting exception info, so that the output may look like:

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