BT: Remove BluetoothExt process foreground handling.

FTP Service startForeground  was required during a active
FTP Session because BluetoothExt process had less proirity
than Bluetooth (com.android.bluetooth) process. This is
not required anymore due to BluetoothExt process runs in
Bluetooth (com.android.bluetooth) process context now.

Removed the relevant code changes to mark the FTPService
in foreground and back to normal priority while active FTP
Session Connect and Disconnect.
This actually reverts commit f32eef886d7429dcf07d4499ae970b1e71279b30.

Change-Id: If3619f5d0a952ace9e4dcbef3a923fff678fe1a0
CRs-Fixed: 765862
4 files changed