Update DEPS to latest linter (0.1.26).

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.
 
 vars = {
   # The dart_root is the root of our sdk checkout. This is normally
   # simply sdk, but if using special gclient specs it can be different.
   "dart_root": "sdk",
 
   # We use mirrors of all github repos to guarantee reproducibility and
@@ skipping 53 matching lines @@
   "http_parser_tag" : "@3.0.2",
   "http_tag" : "@0.11.3+9",
   "http_throttle_rev" : "@284344cd357e435c6c8ff9a4a21f02b9e384a541",
   "idl_parser_rev": "@7fbe68cab90c38147dee4f48c30ad0d496c17915",
   "initialize_tag": "@v0.6.2+2",
   "intl_tag": "@0.13.1",
   "isolate_tag": "@0.2.3",
   "jinja2_rev": "@2222b31554f03e62600cd7e383376a7c187967a1",
   "json_rpc_2_tag": "@2.0.2",
   "kernel_rev": "@9509d282a62fe025f8d6242bb233b02e0a7fee04",
-  "linter_tag": "@0.1.24",
+  "linter_tag": "@0.1.26",
   "logging_tag": "@0.11.3+1",
   "markdown_rev": "@4aaadf3d940bb172e1f6285af4d2b1710d309982",
   "matcher_tag": "@0.12.0+2",
   "metatest_tag": "@0.2.2+2",
   "mime_rev": "@75890811d4af5af080351ba8a2853ad4c8df98dd",
   "mustache4dart_tag" : "@v1.0.10",
   "oauth2_tag": "@1.0.2",
   "observatory_pub_packages_rev": "@a01235b5b71df27b602dae4676d0bf771cbe7fa2",
   "observe_tag": "@0.13.5",
   "package_config_tag": "@1.0.0",
@@ skipping 401 matching lines @@
       "--extract",
       "-s",
       Var('dart_root') + "/third_party/clang.tar.gz.sha1",
     ],
   },
   {
     "pattern": ".",
     "action": ["python", Var("dart_root") + "/tools/gyp_dart.py"],
   },
 ]