Rename shell namespace to service_manager

ash/autoclick/mus/main.cc

Index: ash/autoclick/mus/main.cc
diff --git a/ash/autoclick/mus/main.cc b/ash/autoclick/mus/main.cc
index 6a3643daa11be12d83da47e30962025bb7ca4881..805d709f0201ac5c414de5bfb793782d4331aba5 100644
--- a/ash/autoclick/mus/main.cc
+++ b/ash/autoclick/mus/main.cc
@@ -7,6 +7,7 @@
 #include "services/service_manager/public/cpp/service_runner.h"
 
 MojoResult ServiceMain(MojoHandle service_request_handle) {
-  shell::ServiceRunner runner(new ash::autoclick::AutoclickApplication);
+  service_manager::ServiceRunner runner(
+      new ash::autoclick::AutoclickApplication);
   return runner.Run(service_request_handle);
 }