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/stubs.c b/libbacktrace/stubs.c
index 1741601..f1b055f 100644
--- a/libbacktrace/stubs.c
+++ b/libbacktrace/stubs.c
@@ -16,7 +16,7 @@
 
 #define LOG_TAG "libbacktrace"
 
-#include <cutils/log.h>
+#include <log/log.h>
 #include <backtrace/backtrace.h>
 
 bool backtrace_get_data(backtrace_t* backtrace, pid_t tid) {