Move cutils/log.h to log/log.h.

The log.h file moved, so clean up these references to the old
location.

Change-Id: I25494ea069bfb20fa07a02e67868c8be82e60161
diff --git a/libbacktrace/common.c b/libbacktrace/common.c
index 20786f4..4a6dbfa 100644
--- a/libbacktrace/common.c
+++ b/libbacktrace/common.c
@@ -21,7 +21,7 @@
 #include <sys/ptrace.h>
 #include <inttypes.h>
 
-#include <cutils/log.h>
+#include <log/log.h>
 #include <backtrace/backtrace.h>
 
 #include "common.h"