Update vesta-nginx.conf

Update to CentOS 7 comand!

install/rhel/7/monit/vesta-nginx.conf

@@ -1,3 +1,3 @@
 check process vesta-nginx with pidfile /var/run/vesta-nginx.pid
-    start program = "/etc/init.d/vesta start"
-    stop program  = "/etc/init.d/vesta stop"
+    start program = "/usr/bin/systemctl start vesta"
+    stop program  = "/usr/bin/systemctl stop vesta"