CC-4114: use liquidsoap shutdown() command to restart liquidsoap

-shutdown liquidsoap on install

install_minimal/airtime-install

@@ -178,6 +178,9 @@ fi
 if [ -e /etc/init.d/airtime-playout ]; then
     invoke-rc.d airtime-playout stop > /dev/null 2>&1
 fi
+if [ -e /etc/init.d/airtime-playout ]; then
+    invoke-rc.d airtime-liquidsoap stop > /dev/null 2>&1
+fi
 
 #export these variables to make them available in sub bash scripts
 export DO_UPGRADE

python_apps/pypo/pypofetch.py

@@ -213,7 +213,7 @@ class PypoFetch(Thread):
             self.logger.info("Restarting Liquidsoap")
             subprocess.call('/etc/init.d/airtime-liquidsoap restart', shell=True)
 
-            #Wait here until Liquidsoap has started up
+            #Wait here and poll Liquidsoap until it has started up
             self.logger.info("Waiting for Liquidsoap to start")
             while True:
                 try: