Encourage developers to connect RFCOMM by UUID instead of Channel.

Hide createRfcommSocket(int channel)
Add createRfcommSocketWithServiceRecord(UUID uuid)

Rename listenUsingRfcomm(String,UUID) -> listenUsingRfcommWithServiceRecord(..)

Now we have a complete API for developers to make peer-peer RFCOMM connections
with hard-coding the limited (30) RFCOMM channels, instead using SDP lookup
of an UUID.

This commit addresses two serious bugs:
- Do not throw IOException on accepting an incoming RFCOMM connection with
  BluetoothSocket. This was a regression from commit 24bb9b8a
- Workaround failure of bluez to update SDP cache when channel changes by
  trying to use the same RFCOMM channel on the server every time, instead
  of picking server channels randomly. This is a pretty ugly workaround,
  and we are still trying to fix the caching issue - but with this
  workaround we are at least shippable and apps will work at least until
  they start colliding on the 30 RFCOMM channels.

DrNo: eastham
Bug: 2158900
Joke: What did the digital watch say to his mom? "Look mom no hands."
Change-Id: Ia4879943b83afac06b6f1a3f2391cf1628afce7d