Update V8 DEPS.

Rolling v8/tools/swarming_client to 8fce79620b04bbe5415ace1103db27505bdc4c06

TBR=machenbach@chromium.org,vogelheim@chromium.org,hablich@chromium.org

Review URL: https://codereview.chromium.org/1412173007

Cr-Commit-Position: refs/heads/master@{#31451}

DEPS

@@ -14,7 +14,7 @@ deps = {
   "v8/buildtools":
     Var("git_url") + "/chromium/buildtools.git" + "@" + "ef7f1f539cff0441c4401d8c052e54cfd01bff07",
   "v8/tools/swarming_client":
-    Var('git_url') + '/external/swarming.client.git' + '@' + "b64f0423ee66e730b0ceb88de8b9b89a98d7b61a",
+    Var('git_url') + '/external/swarming.client.git' + '@' + "8fce79620b04bbe5415ace1103db27505bdc4c06",
   "v8/testing/gtest":
     Var("git_url") + "/external/github.com/google/googletest.git" + "@" + "6f8a66431cb592dad629028a50b3dd418a408c87",
   "v8/testing/gmock":