Use md5 symbol exported by util in echo_client.py.
Use md5 symbol exported by util in echo_client.py.

Review URL: http://codereview.appspot.com/4245057

git-svn-id: d23f85197b9dafcb1b1682eb9d0eda70517bdc52@431 4ff78f4a-9131-11de-b045-6380ec9940d4

bpsinc-native/src_third_party_pywebsocket_src,bpsinc-native/src_third_party_pywebsocket_src,bpsinc-native/src_third_party_pywebsocket_src,bpsinc-native/src_third_party_pywebsocket_src