audio_coding: rename interface -> include

BUG=webrtc:5095
R=henrik.lundin@webrtc.org
TBR=tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1417173004 .

Cr-Commit-Position: refs/heads/master@{#10444}
diff --git a/webrtc/modules/audio_coding/codecs/opus/opus.gypi b/webrtc/modules/audio_coding/codecs/opus/opus.gypi
index 5a420b4..05da3e5 100644
--- a/webrtc/modules/audio_coding/codecs/opus/opus.gypi
+++ b/webrtc/modules/audio_coding/codecs/opus/opus.gypi
@@ -45,9 +45,9 @@
       'sources': [
         'audio_decoder_opus.cc',
         'audio_encoder_opus.cc',
-        'interface/audio_decoder_opus.h',
-        'interface/audio_encoder_opus.h',
-        'interface/opus_interface.h',
+        'include/audio_decoder_opus.h',
+        'include/audio_encoder_opus.h',
+        'include/opus_interface.h',
         'opus_inst.h',
         'opus_interface.c',
       ],