Android: Fix crash in QBluetoothServer::close()

Java's BluetoothSocketServer.accept() is meant to be interrupted
via BluetoothSocketServer.close(). Unfortunately if the surrounding
thread is a QThread the returning accept call crashes the thread. This
does not happen if it is a Java Thread.

This commit changes the server's private backend to a Java thread.

Task-number: QTBUG-36754
Change-Id: I5aacc5444bbcd1275a11743b6aa04d2b11a5b22b
Reviewed-by: Nedim Hadzic <nedimhadzija@gmail.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Fix crash when interrupting QBluetoothSocket's input stream thread

The previous QThread did not always properly resume when
InputStream.read() was interrupted by BluetoothSocket.close().
This patch converts the QThread to a Java thread which works
as the Android API docs suggested.

Task-number: QTBUG-37061
Change-Id: Id6ac9b57a28f3b532cbe49ff1dfdc9d1e6432aaa
Reviewed-by: Nedim Hadzic <nedimhadzija@gmail.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>