Update return codes for LSB compliance

start when already running and stop when already stopped should return successful return codes (0)

etc/init.d/proxysql

@@ -82,7 +82,7 @@ start() {
 		fi
 	else
 		echo "ProxySQL is already running."
-		exit 1
+		exit 0
 	fi
 }
 
@@ -92,7 +92,7 @@ stop() {
   if [ "X$pid" = "X" ]
 	then
 		echo "ProxySQL was not running."
-		exit 1
+		exit 0
 	else
 		# Note: we send a kill to all the processes, not just to the child
 		for i in `pgrep proxysql` ; do