package/avahi: drop most of the AVAHI_CONF_ENV vars

Most are legacy from when the package was added and not really necessary.

This commit is based on dropping the CONF_ENV vars in libgtk2 [1].

[1] https://git.buildroot.net/buildroot/commit/package/libgtk2/libgtk2.mk?id=4d80cbdf6c2c186da26f36575d6635604f00d29a

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
1 file changed