Resolve an issue with Diffusion URI parsing ignoring some information

Summary: Fixes T7011. Recent refactoring here caused us to begin ignoring URI parameters like commit. Most controllers take parameters as a dblob, which was still parsed properly.

Test Plan:

• Editing different commits actually edits the desired commits.
• Browsed around some dblob pages and verified they still work properly.

Reviewers: btrahan, chad

Reviewed By: chad

Subscribers: epriestley

Maniphest Tasks: T7011

Differential Revision: https://secure.phabricator.com/D11473