Prefix LOG and CHECK with AOS_

This prepares us for introducing glog more widely and transitioning
things over where they make sense.

Change-Id: Ic6c208882407bc2153fe875ffc736d66f5c8ade5
diff --git a/aos/protobuf/stack_arena.cc b/aos/protobuf/stack_arena.cc
index da9b004..c085fcb 100644
--- a/aos/protobuf/stack_arena.cc
+++ b/aos/protobuf/stack_arena.cc
@@ -4,11 +4,11 @@
 namespace protobuf {
 
 void FatalArenaBlockAlloc(size_t) {
-  LOG(FATAL, "trying to allocate in arena code");
+  AOS_LOG(FATAL, "trying to allocate in arena code");
 }
 
 void FatalArenaBlockDealloc(void*, size_t) {
-  LOG(FATAL, "trying to deallocate in arena code");
+  AOS_LOG(FATAL, "trying to deallocate in arena code");
 }
 
 }  // namespace protobuf