avahi-client: remove deprecated methods which throw errors.
avahi-client: remove deprecated methods which throw errors.

They were wrapper methods which caused a dependency on avahi-gobject
which should not exist.  They were deprecated several years ago with
the goal of removing them at some point, and I think that time has
come.

rvu95/vala,frida/vala,flobrosch/vala-fixes,rvu95/vala,flobrosch/vala-fixes,Distrotech/vala,flobrosch/vala-fixes,spidermonkdust/vala,frida/vala,GNOME/vala,frida/vala,GNOME/vala,rvu95/vala,GNOME/vala,frida/vala,spidermonkdust/vala,frida/vala,GNOME/vala,spidermonkdust/vala,Distrotech/vala,Distrotech/vala