Upgrade gflags to master

Merge commit 'cb7bb2b58469b0ba5132fbcf4893b2ca76dead1c' into master

Change-Id: Id6b07c15b3bef794984d6f326d6596f043d1dde5
diff --git a/third_party/gflags/WORKSPACE b/third_party/gflags/WORKSPACE
new file mode 100644
index 0000000..f3707e9
--- /dev/null
+++ b/third_party/gflags/WORKSPACE
@@ -0,0 +1,6 @@
+# Copyright 2006 Google Inc.  All Rights Reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the COPYING.txt file.
+
+# Bazel (http://bazel.io/) WORKSPACE file for gflags.
+workspace(name="com_github_gflags_gflags")