Fix: restore the correct URL to browse files on git

commits.kde.org is the generic redirector and it must always be used.
It will point to the right location when, at some point, we will move
to phabricator as primary git browser instead of cgit, and for any
possible future migration.

For reference:
https://techbase.kde.org/Projects/Documentation/KDE_(health_table)#Links_to_kde_repos

CCMAIL: nikita+kde@melnichenko.name