Change mojo URLs from mojo://mojo_foo to mojo://foo.

mojo/examples/echo/echo_client.cc

Index: mojo/examples/echo/echo_client.cc
diff --git a/mojo/examples/echo/echo_client.cc b/mojo/examples/echo/echo_client.cc
index 2eeae0d2cc897f789a973f624c5db08b09e4d387..1d44d08e03f9ffa1bcf36d79c9b21903a896a3a9 100644
--- a/mojo/examples/echo/echo_client.cc
+++ b/mojo/examples/echo/echo_client.cc
@@ -26,7 +26,7 @@ class ResponsePrinter {
 class EchoClientDelegate : public ApplicationDelegate {
  public:
   virtual void Initialize(ApplicationImpl* app) override {
-    app->ConnectToService("mojo:mojo_echo_service", &echo_service_);
+    app->ConnectToService("mojo:echo_service", &echo_service_);
 
     echo_service_->EchoString("hello world", ResponsePrinter());
   }