Nest some more namespaces

Did someone previously suggest that all namespace had been
nested?  Silly.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I22278c1caaeba8b47dc46fb2ed3078c20a11e190
diff --git a/motors/print/usb.h b/motors/print/usb.h
index c2224d2..5e811b3 100644
--- a/motors/print/usb.h
+++ b/motors/print/usb.h
@@ -5,8 +5,7 @@
 #include "motors/usb/cdc.h"
 #include "motors/usb/usb.h"
 
-namespace frc971 {
-namespace motors {
+namespace frc971::motors {
 
 // A printing implementation which uses externally-created functions. The stdout
 // one is required, while the debug one is optional.
@@ -68,7 +67,6 @@
   teensy::AcmTty debug_tty_;
 };
 
-}  // namespace motors
-}  // namespace frc971
+}  // namespace frc971::motors
 
 #endif  // MOTORS_PRINT_USB_H_