vncserver: fix heredoc to work on CentOS

unix/vncserver

@@ -562,10 +562,10 @@ sub CheckUserHasAccessToDefaultCertOnDebian {
 
   my $certGroup = 'ssl-cert';
   if (system("groups | grep -qw $certGroup") != 0) {
-    say <<~EOF;
+    say <<EOF;
-      Can't access TLS certificate.
+  Can't access TLS certificate.
-      Please add your user to $certGroup via 'addgroup <user> $certGroup'
+  Please add your user to $certGroup via 'addgroup <user> $certGroup'
-    EOF
+EOF
     exit(1);
   }
 }