DO NOT MERGE ANYWHERE

Set initial default supported audio routes for Call object.

CallAudioManager may reference the Call before a connection has been
selected. In these cases, the supported audio routes should reflect all
possible routes (default) possible. Currently, returning 0 is causing no
route to be possible, leading to a wtf log.

Bug: 26579826
Change-Id: I500a20ed8d9599f00a3f365a26e99b0fafd003c4