Fix presubmit check for the case when cpplint fails.

tools/presubmit.py

Index: tools/presubmit.py
diff --git a/tools/presubmit.py b/tools/presubmit.py
index a5f4c614d04a800c816991bdc6a00f27101aa5f1..c606e42e69db5ecd97033f783c929e4b91b8d151 100755
--- a/tools/presubmit.py
+++ b/tools/presubmit.py
@@ -114,12 +114,15 @@ def CppLintWorker(command):
     while True:
       out_line = process.stderr.readline()
       if out_line == '' and process.poll() != None:
+        if error_count == -1:
+          print "Failed to process %s" % command.pop()
+          return 1
         break
       m = LINT_OUTPUT_PATTERN.match(out_line)
       if m:
         out_lines += out_line
         error_count += 1
-    sys.stderr.write(out_lines)
+    sys.stdout.write(out_lines)
     return error_count
   except KeyboardInterrupt:
     process.kill()