init: support for not loading vchan-sink

rootfs/init

@@ -44,13 +44,22 @@ if [ -n "$audio_model" ] ; then
     fi
     export XDG_CONFIG_HOME='/tmp'
     pa_args=$'-audiodev\npa,id=qemupa,server=unix:/tmp/pa.sock'$model_args;
-    pulseaudio --use-pid-file=no --daemonize=no --exit-idle-time=-1 -n \
-	-L "module-native-protocol-unix auth-anonymous=1 socket=/tmp/pa.sock" \
-	-L "module-always-sink" \
-	-L "module-always-source" \
-	-L "module-null-sink" \
-	-L "module-null-source" \
-	-L "module-vchan-sink domid=$domid" &
+    if [ "$domid" -ge 0 ]; then
+        pulseaudio --use-pid-file=no --daemonize=no --exit-idle-time=-1 -n \
+            -L "module-native-protocol-unix auth-anonymous=1 socket=/tmp/pa.sock" \
+            -L "module-vchan-sink domid=$domid" \
+            -L "module-always-sink" \
+            -L "module-always-source" \
+            -L "module-null-sink" \
+            -L "module-null-source" &
+    else
+        pulseaudio --use-pid-file=no --daemonize=no --exit-idle-time=-1 -n \
+            -L "module-native-protocol-unix auth-anonymous=1 socket=/tmp/pa.sock" \
+            -L "module-always-sink" \
+            -L "module-always-source" \
+            -L "module-null-sink" \
+            -L "module-null-source" &
+    fi
 fi
 
 # Extract network parameters and remove them from dm_args