Move logging.h into base/logging.h.

Change-Id: Id68f85f7c3a71b156cb40dec63f94d4fb827f279
diff --git a/src/signal_set.h b/src/signal_set.h
index 030a2d1..d4aec86 100644
--- a/src/signal_set.h
+++ b/src/signal_set.h
@@ -19,7 +19,7 @@
 
 #include <signal.h>
 
-#include "logging.h"
+#include "base/logging.h"
 
 namespace art {