Save ApplicationSearch queries generated from GET parameters in the request

Summary:
Fixes T4239. Currently, if you go to `/maniphest/?authors=alincoln`, operations dependent on the query key (like "Save Custom Query..." and "Export to Excel...") don't have a query key to work with. Make sure they have one.

Also remove a stray `phlog()`.

Test Plan: "Save Custom Query...", etc., now work on GET queries.

Reviewers: btrahan, chad

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T4239

Differential Revision: https://secure.phabricator.com/D7777