libcutils: turn on -Werror

- Deal with some -Wunused / -Wunused-variable issues

Change-Id: I28c23fb213382a392ec30935749fb359e072d664
diff --git a/libcutils/trace.c b/libcutils/trace.c
index 9754a44..f57aac2 100644
--- a/libcutils/trace.c
+++ b/libcutils/trace.c
@@ -28,7 +28,7 @@
 #include <cutils/trace.h>
 
 #define LOG_TAG "cutils-trace"
-#include <cutils/log.h>
+#include <log/log.h>
 
 volatile int32_t        atrace_is_ready      = 0;
 int                     atrace_marker_fd     = -1;
@@ -86,7 +86,6 @@
 static bool atrace_is_app_tracing_enabled()
 {
     bool sys_debuggable = false;
-    bool proc_debuggable = false;
     char value[PROPERTY_VALUE_MAX];
     bool result = false;