Ignore Unicode errors when executing vboxmanage.

gns3server/modules/virtualbox/__init__.py

@@ -724,7 +724,7 @@ class VirtualBox(IModule):
             result = subprocess.check_output(command, stderr=subprocess.STDOUT, timeout=30)
         except (OSError, subprocess.SubprocessError) as e:
             raise VirtualBoxError("Could not execute VBoxManage {}".format(e))
-        return result.decode("utf-8")
+        return result.decode("utf-8", errors="ignore")
 
     @IModule.route("virtualbox.vm_list")
     def vm_list(self, request):

gns3server/modules/virtualbox/virtualbox_vm.py

@@ -560,7 +560,7 @@ class VirtualBoxVM(object):
                 raise VirtualBoxError("{}".format(e))
         except (OSError, subprocess.SubprocessError) as e:
             raise VirtualBoxError("Could not execute VBoxManage: {}".format(e))
-        return result.decode("utf-8").splitlines()
+        return result.decode("utf-8", errors="ignore").splitlines()
 
     def _get_vm_info(self):
         """