Handle os-release more smartly

The Qt ports, and GNOME control center, can read /etc/os-release,
and have patches to read /usr/local/etc/os-release -- however,
the two files update differently, and /etc/os-release is preferred.
Tighten up the .if to select when to depend on the extra
port for /usr/local/etc/os-release (basically: pre 11.4 and 12.1)

• Bumps PORTREVISION because dependencies may change.
• Note that I used the --author command-line option to set that mikael@ wrote this patch.

PR: 251073