Fix warning that the file /etc/rspamd/local.d/worker-controller.inc does not exists during installation.

Author: Till Brehm

install/lib/installer_base.lib.php

@@ -1981,8 +1981,13 @@ public function configure_rspamd() {
 
 		exec('chmod a+r /etc/rspamd/local.d/* /etc/rspamd/local.d/maps.d/* /etc/rspamd/override.d/*');
 		# protect passwords in these files
-		exec('chgrp _rspamd /etc/rspamd/local.d/redis.conf /etc/rspamd/local.d/classifier-bayes.conf /etc/rspamd/local.d/worker-controller.inc');
-		exec('chmod 640 /etc/rspamd/local.d/redis.conf /etc/rspamd/local.d/classifier-bayes.conf /etc/rspamd/local.d/worker-controller.inc');
+		exec('chgrp _rspamd /etc/rspamd/local.d/redis.conf /etc/rspamd/local.d/classifier-bayes.conf');
+		exec('chmod 640 /etc/rspamd/local.d/redis.conf /etc/rspamd/local.d/classifier-bayes.conf');
+
+		if(file_exists('/etc/rspamd/local.d/worker-controller.inc')) {
+			exec('chgrp _rspamd /etc/rspamd/local.d/worker-controller.inc');
+			exec('chmod 640 /etc/rspamd/local.d/worker-controller.inc');
+		}
 
 		# unneccesary, since this was done above?
 		$command = 'usermod -a -G amavis _rspamd';