Delete VoiceChannelTransport before deleting Channel in voe_cmd_test

Current voe_cmd_test shows following error when quitting:
DeRegisterExternalTransport() failed to locate channel.

This is to fix it.

BUG=
R=henrika@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/45349004

Cr-Commit-Position: refs/heads/master@{#9129}
diff --git a/webrtc/voice_engine/test/cmd_test/voe_cmd_test.cc b/webrtc/voice_engine/test/cmd_test/voe_cmd_test.cc
index 9133a07..ee9306d 100644
--- a/webrtc/voice_engine/test/cmd_test/voe_cmd_test.cc
+++ b/webrtc/voice_engine/test/cmd_test/voe_cmd_test.cc
@@ -260,7 +260,7 @@
     fflush(NULL);
   }
 
-  rtc::scoped_ptr<VoiceChannelTransport> voice_channel_transport(
+  VoiceChannelTransport* voice_channel_transport(
       new VoiceChannelTransport(netw, chan));
 
   char ip[64];
@@ -845,6 +845,9 @@
     newcall = (end_option == 1);
     // Call loop
   }
+
+  // Transports should be deleted before channel deletion.
+  delete voice_channel_transport;
   for (int i = 0; i < kMaxNumChannels; ++i) {
     delete voice_channel_transports[i];
     voice_channel_transports[i] = NULL;
@@ -855,7 +858,7 @@
   VALIDATE;
 
   for (int i = 0; i < kMaxNumChannels; ++i) {
-    channels[i] = base1->DeleteChannel(channels[i]);
+    res = base1->DeleteChannel(channels[i]);
     VALIDATE;
   }
 }