Fixed a memory leak from the thread name.

Change-Id: I291c16b54b48bddf9240c8aecc7261030fae3466
diff --git a/aos/common/logging/logging_impl.cc b/aos/common/logging/logging_impl.cc
index 724d4b8..c776991 100644
--- a/aos/common/logging/logging_impl.cc
+++ b/aos/common/logging/logging_impl.cc
@@ -80,8 +80,8 @@
 
   message->level = level;
   message->source = context->source;
-  memcpy(message->name, context->name.c_str(), context->name.size());
-  message->name_length = context->name.size();
+  memcpy(message->name, context->name, context->name_size);
+  message->name_length = context->name_size;
 
   time::Time now = time::Time::Now();
   message->seconds = now.sec();