build: Don't install a top level copy of audio_processing.h

If we're breaking API, then clients need to be modified and recompiled
anyway, so we can avoid the cruft of trying to be backwards compatible.

Clients now need to include the file as it is in the upstream sources:
<webrtc/modules/audio_processing/include/audio_processing.h>

Makefile.am

@@ -14,5 +14,3 @@ nobase_webrtcinclude_HEADERS = webrtc/base/arraysize.h \
 			       webrtc/modules/audio_processing/beamformer/array_util.h \
 			       webrtc/modules/audio_processing/include/audio_processing.h \
 			       webrtc/modules/interface/module_common_types.h
-# FIXME: We should deprecate installing this to the top directory soon
-webrtcinclude_HEADERS = webrtc/modules/audio_processing/include/audio_processing.h