Allow Feed HTTP hooks to be https://
Summary: Fixes T3503. "HTTPFuture" is specialized and HTTP-only; "HTTPSFuture" is generalized and HTTP+HTTPS.
Test Plan: yeah not so much
Reviewers: btrahan, edward
Reviewed By: edward
CC: aran
Maniphest Tasks: T3503
Differential Revision: https://secure.phabricator.com/D6378