Mention the security warning from the browser at installation completion

Author: swelljoe

virtualmin-install.sh

@@ -927,6 +927,7 @@ if [ $errors -eq "0" ]; then
   log_success "Installation Complete!"
   log_success "If there were no errors above, Virtualmin should be ready"
   log_success "to configure at https://$hostname:10000."
+  log_success "You'll receive a security warning in your browser on your first visit."
 else
   log_warning "The following errors occurred during installation:"
   echo