Do not pass silently on ClientResponseError

[pombredanne]

Several importers or fetcher fail silently on ClientResponseError such as here https://github.com/nexB/vulnerablecode/blob/24e33966bae6124e381556e520e18f1129c352fc/vulnerabilities/package_managers.py#L147

We should never fail silently unless it is really needed.

[SahilKhanWDC]

Hello maintainers!!
If someone is not currently working on this issue then i would like to work on it.
If you can assign this issue to me ?