Update path for audioproc_debug proto output.

This will make it align with protoc tools that use the relative
path from the project root to the files in the output path.
Having this, no hacks will need to be applied downstream.

TBR=henrik.lundin@webrtc.org
NOTRY=True

Review URL: https://codereview.webrtc.org/1673263002

Cr-Commit-Position: refs/heads/master@{#11540}

webrtc/modules/audio_processing/test/unpack.cc

@@ -16,9 +16,9 @@
 #include <stdio.h>
 
 #include "gflags/gflags.h"
-#include "webrtc/audio_processing/debug.pb.h"
 #include "webrtc/base/format_macros.h"
 #include "webrtc/base/scoped_ptr.h"
+#include "webrtc/modules/audio_processing/debug.pb.h"
 #include "webrtc/modules/audio_processing/test/protobuf_utils.h"
 #include "webrtc/modules/audio_processing/test/test_utils.h"
 #include "webrtc/typedefs.h"