Use telecomm DiconnectCause in services/Telecomm.

+ Some of this is straightforward replacing the old disconnect cause
code/message with the new DisconnectCause object.
+ Replace codes in some instances; most maps straightforwardly to the
newer generic set of disconnect causes.
+ InCallToneMonitor can no longer rely on the specific telephony
DisconnectCauses. Now, instead, they map from a tone (which is
specified on the new telecomm DisconnectCauses) to the type of tone
which should be played in InCall. Most of these are just taking
unique matches from InCallTonePlayer. It is a little redundant, as
the conversion just flips, but it seemed like the easiest way to
accomplish this given current constraints.

+ Behavior is unchanged, but now DisconnectCause.OUT_OF_SERVICE
will invoke InCallTonePlayer.TONE_CDMA_DROP.
+ Now play TONE_PROP_PROMPT regardless of whether there is precisely
one remaining call; this is because we can't distinguish between
telephony DisconnectCause.ERROR_UNSPECIFIED/NORMAL/LOCAL. I figured
this would be a relatively minor change in scenario, and it wouldn't
hurt for a tone to be played even in a disconnect in that scenario.

Bug: 17329632
Change-Id: I85767d424bcfd59b3929819c9c6de46fc4a8629e