Update Closure Rules dependency to HEAD

This makes the definition consistent with TensorBoard and TensorFlow
Serving. It's better to track HEAD than the release versions.

PiperOrigin-RevId: 170788851

WORKSPACE

@@ -2,11 +2,11 @@ workspace(name = "org_tensorflow")
 
 http_archive(
     name = "io_bazel_rules_closure",
-    sha256 = "25f5399f18d8bf9ce435f85c6bbf671ec4820bc4396b3022cc5dc4bc66303609",
-    strip_prefix = "rules_closure-0.4.2",
+    sha256 = "110fe68753413777944b473c25eed6368c4a0487cee23a7bac1b13cc49d3e257",
+    strip_prefix = "rules_closure-4af89ef1db659eb41f110df189b67d4cf14073e1",
     urls = [
-        "http://mirror.bazel.build/github.com/bazelbuild/rules_closure/archive/0.4.2.tar.gz",  # 2017-08-29
-        "https://github.com/bazelbuild/rules_closure/archive/0.4.2.tar.gz",
+        "http://mirror.bazel.build/github.com/bazelbuild/rules_closure/archive/4af89ef1db659eb41f110df189b67d4cf14073e1.tar.gz",
+        "https://github.com/bazelbuild/rules_closure/archive/4af89ef1db659eb41f110df189b67d4cf14073e1.tar.gz",  # 2017-08-28
     ],
 )