Move //mojo/services/X/public/... to //mojo/services/X/... (part 4).

X = vanadium/security,
    view_manager,
    window_manager

(This is the last one, except for network, which is pulled from monet.)

R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/1391243003 .
diff --git a/examples/bank_app/customer.cc b/examples/bank_app/customer.cc
index 5533f5d..7fb227f 100644
--- a/examples/bank_app/customer.cc
+++ b/examples/bank_app/customer.cc
@@ -9,7 +9,7 @@
 #include "mojo/public/cpp/application/application_impl.h"
 #include "mojo/public/cpp/application/application_runner.h"
 #include "mojo/public/cpp/utility/run_loop.h"
-#include "mojo/services/vanadium/security/public/interfaces/principal.mojom.h"
+#include "mojo/services/vanadium/security/interfaces/principal.mojom.h"
 
 namespace examples {