CEC: Fix two bugs

- <Routing Change> goes out with invalid parameter (F.F.F.F) for
  old path if the active source/path is not set. Should have been
  set to internal path (0.0.0.0)
- <User Control Pressed> was still sent when active source was not
  set. Fixed to discard it.

Bug: 16966486
Bug: 16965446
Change-Id: I5abb062be42c17514b3ed7ac930d7a3535fc9132