Throw a more friendly error message if establishing SSL / TLS connection fails

[Kami]

With this change we now throw a more user-friendly error message in case establishing SSL / TLS connection fails.

New error message:

  File "/home/kami/w/lc/libcloud/libcloud/httplib_ssl.py", line 312, in connect
    raise new_e
socket.error: Failed to establish SSL / TLS connection ([Errno 104] Connection reset by peer). It is possible that the server doesn't support requested SSL / TLS version (TLS v1.0).
For information on how to work around this issue, please see https://libcloud.readthedocs.org/en/latest/other/ssl-certificate-validation.html#changing-used-ssl-tls-version

Related to https://issues.apache.org/jira/browse/LIBCLOUD-791

[jimbobhickville]

Shouldn't we limit this to the specific exception type(s) that might exhibit this behavior? Looked like it was socket.error in the JIRA.

[Kami]

Yeah, that's a good idea - I will make that change.

[Kami]

Done.

Also committed some tests (previously I forgot to add the test file).