Omit protocol part in URLs in changelog pages.
Reason for this change:
In the past, build.chromium.org
was HTTP-only, and so it couldn't be directly put in an iframe on the perf dashboard which uses HTTPS. Annie Sullivan made a page on the perf dashboard, /revision_proxy to get around this.
supports HTTPS, and I wanted to switch the changelog viewer links that the dashboard uses to HTTPS. The purpose of this CL is to make the changelog viewer pages work the same with both HTTP and HTTPS.