service: Fix environment file parsing
Systemd parses EnvironmentFile
as key value pairs (not as sourced
shell script). Hence it would always pick up the last value pair (0,4).
By actually sourcing the script we get the correct values, e.g. on fachita:
CGroup: /system.slice/q6voiced.service
├─36801 sh -c ". /usr/share/q6voiced/q6voiced.conf && /usr/bin/q6voiced hw:\${q6voice_card},\${q6voice_device}"
└─36806 /usr/bin/q6voiced hw:0,6