Checkmk Werk 13378: Fix detection of HTTP protocol

ID: 13378 Title: Fix detection of HTTP protocol Component: Multisite Level: 1 Class: Bug fix Version: 2.1.0i1 The detection of the HTTP protocol, used in "Analyze configuration", "Crash reports" and to determine the shown default setting of "URL prefix for links to Checkmk" for notifications, was broken since 2.0.0. That leaded e.g. to a warning in section "Secure GUI (HTTP)" of "Analyze configuration", even if https was configured.