Nest all namespaces

The compiler supports this now.  We can type less going forward.
No functional changes.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I29d6fa4f9aacc0e381f1a7637294db0392466995
diff --git a/aos/ipc_lib/lockless_queue.cc b/aos/ipc_lib/lockless_queue.cc
index f033e60..a26b564 100644
--- a/aos/ipc_lib/lockless_queue.cc
+++ b/aos/ipc_lib/lockless_queue.cc
@@ -22,8 +22,7 @@
 DEFINE_bool(dump_lockless_queue_data, false,
             "If true, print the data out when dumping the queue.");
 
-namespace aos {
-namespace ipc_lib {
+namespace aos::ipc_lib {
 namespace {
 
 class GrabQueueSetupLockOrDie {
@@ -1662,5 +1661,4 @@
   ::std::cout << "}" << ::std::endl;
 }
 
-}  // namespace ipc_lib
-}  // namespace aos
+}  // namespace aos::ipc_lib