nicky: remove default bluetooth a2dp lib

See packages/modules/Bluetooth @ f261e756b4f10059b6b90847cd208c95adbd8146

build/make/core/tasks/platform_availability_check.mk:37: warning:

Following modules are requested to be installed. But are not available
for platform because they do not have "//apex_available:platform" or
they depend on other modules that are not available for platform

Offending entries:
  audio.a2dp.default:packages/modules/Bluetooth/system/audio_a2dp_hw
  audio.a2dp.default_32:packages/modules/Bluetooth/system/audio_a2dp_hw

Change-Id: I731879d4ad3b3840a71a172b934fc61d8a493353
Signed-off-by: Alexander Martinz <amartinz@shiftphones.com>