The shairport-sync service currently fails to start with the error
shairport avahi_entry_group_new failed
This problem seems to have been introduced by
cdd7310a50
After some trial and error I concluded that the attached commit is a minimal
fix.
Adds a new service module for shairport-sync. Tested with a local
and remote pulseaudio server. Needs to be run as a user in the pulse group
to access pulseaudio.
