Running without a separate user content instance requires abuse of command line options. #1471

0. I wish to run a local instance of a Hackage server. This is a trusted environment, so I see no need for a separate user content instance. 
1. However, the flags required-base-host-header and user-content-uri are required.
2. Moreover, when they are set all to the same value, say localhost:1024, any request to user content will result in an infinite 301 redirect due to the logic of the function Distribution.Server.Framework.ServerEnv.requireUserContent.

This problem can be overcome by setting required-base-host-header to a nonsensical value. Any string other than the true base host header would do.

I think this should be re-designed. Either the problematic options should be made optional, or an equality check should be added to the problematic logic.

This is the exact command I am running:

hackage-server run --static-dir datafiles --user-content-uri 'http://localhost:1024' --base-uri 'http://localhost:1024' --required-base-host-header 'localhost:1024' --port 1024

The executable file is built from the commit 4231f36.