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/ipc_lib/index.h b/aos/ipc_lib/index.h
index 434da7c..75f1e9b 100644
--- a/aos/ipc_lib/index.h
+++ b/aos/ipc_lib/index.h
@@ -23,8 +23,7 @@
 #endif
 #endif
 
-namespace aos {
-namespace ipc_lib {
+namespace aos::ipc_lib {
 
 struct AtomicQueueIndex;
 class AtomicIndex;
@@ -305,7 +304,6 @@
   ::std::atomic<Index::IndexType> index_;
 };
 
-}  // namespace ipc_lib
-}  // namespace aos
+}  // namespace aos::ipc_lib
 
 #endif  // AOS_IPC_LIB_INDEX_H_