Web Connector: Fix SSL issues in redirections

This is the pull request #164 from Soggard:

https://github.com/apache/manifoldcf/pull/164

We noticed that in some case, when using the new "Force the inclusion of redirections" option in the Web Crawler Connector, we encounter SSL certificate error. This happens when whe try to get the final URL from a redirection in order to add it to the seed.

We can fix this by disabling SSL verification while getting final URL from pages with redirections. The unchecked certificates should not cause any problems, since it's only about adding the new host to the seed. All usual checks will be applied during the indexing.

Note that when fetching the final url, we do not take into account the connector's graphical option to able or disable certificate validation: certificates are always ignored. Still, once the actual crawling takes place when the final list of seed hosts is established, the option about certification validation is respected again.

We can consider this for ManifoldCF 2.28.