Updated observatory_pub_packages dependency

DEPS

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # IMPORTANT:
 # Before adding or updating dependencies, please review the documentation here:
 # https://github.com/dart-lang/sdk/wiki/Adding-and-Updating-Dependencies
 
 vars = {
   # The dart_root is the root of our sdk checkout. This is normally
@@ skipping 82 matching lines @@
   "jinja2_rev": "@2222b31554f03e62600cd7e383376a7c187967a1",
   "json_rpc_2_tag": "@2.0.4",
   "linter_tag": "@0.1.33",
   "logging_tag": "@0.11.3+1",
   "markdown_tag": "@0.11.3",
   "matcher_tag": "@0.12.0+2",
   "mime_rev": "@75890811d4af5af080351ba8a2853ad4c8df98dd",
   "mockito_tag": "@2.0.2",
   "mustache4dart_tag" : "@v1.1.0",
   "oauth2_tag": "@1.0.2",
-  "observatory_pub_packages_rev": "@26aad88f1c1915d39bbcbff3cad589e2402fdcf1",
+  "observatory_pub_packages_rev": "@a4e392521c720d244cd63e067387195d78584b35",
   "package_config_tag": "@1.0.1",
   "package_resolver_tag": "@1.0.2+1",
   "path_tag": "@1.4.1",
   "plugin_tag": "@0.2.0",
   "ply_rev": "@604b32590ffad5cbb82e4afef1d305512d06ae93",
   "pool_tag": "@1.3.0",
   "protobuf_tag": "@0.5.4",
   "pub_rev": "@0f122625f8e607842afe156b9b23a9709e4ce39a",
   "pub_semver_tag": "@1.3.2",
   "quiver_tag": "@0.22.0",
@@ skipping 366 matching lines @@
     # Update the Windows toolchain if necessary.
     'name': 'win_toolchain',
     'pattern': '.',
     'action': ['python', 'sdk/build/vs_toolchain.py', 'update'],
   },
   {
     "pattern": ".",
     "action": ["python", Var("dart_root") + "/tools/generate_buildfiles.py"],
   },
 ]