Forbid unsafe Qemu additional options

conf/gns3_server.conf

@@ -93,6 +93,8 @@ require_kvm = True
 enable_hardware_acceleration = True
 ; Require hardware acceleration in order to start VMs (all platforms)
 require_hardware_acceleration = False
+; Allow unsafe additional command line options
+allow_unsafe_options = False
 
 [VMware]
 ; First vmnet interface of the range that can be managed by the GNS3 server