package/avahi: bump to version 0.6.32

Also:
 * switch download site to github as the previous download page is not
   maintained anymore
 * drop 0004-no-gtk-deprecations.patch as it is applied upstream

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>