Catch OSError exception for subprocess calls.

gns3server/modules/virtualbox/__init__.py

@@ -722,7 +722,7 @@ class VirtualBox(IModule):
 
         try:
             result = subprocess.check_output(command, stderr=subprocess.STDOUT, timeout=30)
-        except subprocess.SubprocessError as e:
+        except (OSError, subprocess.SubprocessError) as e:
             raise VirtualBoxError("Could not execute VBoxManage {}".format(e))
         return result.decode("utf-8")
 

gns3server/modules/virtualbox/virtualbox_vm.py

@@ -558,7 +558,7 @@ class VirtualBoxVM(object):
                 raise VirtualBoxError("{}".format(virtualbox_error))
             else:
                 raise VirtualBoxError("{}".format(e))
-        except subprocess.SubprocessError as e:
+        except (OSError, subprocess.SubprocessError) as e:
             raise VirtualBoxError("Could not execute VBoxManage: {}".format(e))
         return result.decode("utf-8").splitlines()