Don't use default aec_dump in webrtcvoiceengine when non is provided

talk/media/webrtc/webrtcvoiceengine.cc

Index: talk/media/webrtc/webrtcvoiceengine.cc
diff --git a/talk/media/webrtc/webrtcvoiceengine.cc b/talk/media/webrtc/webrtcvoiceengine.cc
index 9eee2af20219d710bfad79104c047ad905f33c76..2caa166d6aae05b7828b2b01eef54b307f040a7a 100644
--- a/talk/media/webrtc/webrtcvoiceengine.cc
+++ b/talk/media/webrtc/webrtcvoiceengine.cc
@@ -585,7 +585,6 @@ bool WebRtcVoiceEngine::ApplyOptions(const AudioOptions& options_in) {
   options.extended_filter_aec = rtc::Optional<bool>(false);
   options.delay_agnostic_aec = rtc::Optional<bool>(false);
   options.experimental_ns = rtc::Optional<bool>(false);
-  options.aec_dump = rtc::Optional<bool>(false);
 
   // Apply any given options on top.
   options.SetAll(options_in);