Do not try to fallback to "less secure" protocols

Summary:
Both Firefox and Chrom[e|ium] do this for a while so most
sites have already make sure they are better compliant
than when we introduced this workaround

Test Plan: Contact a few https sites, still works

Reviewers: stikonas

Reviewed By: stikonas

Subscribers: jtamate, carewolf, dfaure, stikonas, kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D16344