[automerger skipped] Fix that PhoneSwitcher only listens to call state change of default sub.
am: a23d80dd -s ours
am skip reason: change_id Idd21283ba3f01bc99fd9afff7c83a79711649f01 with SHA1 4b88a5c7 is in history
Change-Id: I6bab905cdaedce3cf4c3fb5a3f663605093a22f9