Remove host from the list not to be forwarded

[carloshm]

As https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.23 described, host must be present. I faced problems with apps that expect host to be presented AND to have the URL the client requested.

Type of change?

• [x] Bug fix
• [ ] New feature
• [ ] Enhancement
• [ ] Breaking change (breaks backward compatibility)

Description, Context, Motivation

Testing the reverse proxy with a third party service, their service fails due a mismatch in the host (they use it to confirm encrypted messages. It turned out RP translate the original host header.

Checklist:

• [x] All tests passed
• [x] The code follows the code style and conventions of this project
• [ ] The change requires a change to the documentation
• [ ] I have updated the documentation accordingly

[dluc]

The host header cannot be forwarded, because the proxy hostname differs from the backend hostname. The code takes care of setting a new host when calling the backend.