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/aos/vision/events/udp.h b/aos/vision/events/udp.h
index 3c16b28..4acb04d 100644
--- a/aos/vision/events/udp.h
+++ b/aos/vision/events/udp.h
@@ -12,8 +12,7 @@
 #include "aos/macros.h"
 #include "aos/scoped/scoped_fd.h"
 
-namespace aos {
-namespace events {
+namespace aos::events {
 
 // Simple wrapper around a transmitting UDP socket.
 //
@@ -67,7 +66,6 @@
   DISALLOW_COPY_AND_ASSIGN(RXUdpSocket);
 };
 
-}  // namespace events
-}  // namespace aos
+}  // namespace aos::events
 
 #endif  // AOS_VISION_EVENTS_UDP_H_