Roll tools/swarming_client/ to 2cbc12487aea464730bcf60230f4d4d63d61ac51.

$ git log c8437bfa4..2cbc12487 --date=short --format='%ad %ae %s' | sed 's/@chromium\.org//'
2014-07-16 maruel Fix a crash in run_isolated.py when the cache is not used.
2014-07-14 maruel Enforce the use of --priority in run_on_bots.py.
2014-07-11 maruel Fix run_on_bots.py to not assume id == hostname.

R=csharp@chromium.org
BUG=

Review URL: https://codereview.chromium.org/397043002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283690 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -61,7 +61,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling swarming_client
   # and whatever else without interference from each other.
-  "swarming_revision": "c8437bfa40aa3428ee7655585b6203f2cac67693",
+  "swarming_revision": "2cbc12487aea464730bcf60230f4d4d63d61ac51",
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling openssl
   # and whatever else without interference from each other.