Revert "Followup c41f96c: doc parameter in ve.dm.InternalList constructor is not optional, remove check"

> Uncaught TypeError: Cannot call method 'connect' of undefined

This reverts commit fb4dcf30302aa8ab449ce9f7870f3b55a0326223.

Change-Id: I9db92e7bf339260d8de0a9406842bdb241b8ee80
Merge "Revert "Followup c41f96c: doc parameter in ve.dm.InternalList constructor is not optional, remove check""