Rename shell namespace to service_manager

mash/task_viewer/main.cc

Index: mash/task_viewer/main.cc
diff --git a/mash/task_viewer/main.cc b/mash/task_viewer/main.cc
index 3bb7c4cfbc5a608622fea3fd7e3908a6e9d9f88a..5ec9e95ebc1f092b149358a2d5c1eaa68579e63e 100644
--- a/mash/task_viewer/main.cc
+++ b/mash/task_viewer/main.cc
@@ -7,6 +7,6 @@
 #include "services/service_manager/public/cpp/service_runner.h"
 
 MojoResult ServiceMain(MojoHandle service_request_handle) {
-  shell::ServiceRunner runner(new mash::task_viewer::TaskViewer);
+  service_manager::ServiceRunner runner(new mash::task_viewer::TaskViewer);
   return runner.Run(service_request_handle);
 }