Log Message:
Update py-oauth2client to 1.5.2.

Needed by py-google-api-python-client-1.4.2.

## v1.5.2

* Add access token refresh error class that includes HTTP status (#310)
* Python3 compatibility fixes for Django (#316, #318)
* Fix incremental auth in flask_util (#322)
* Fall back to credential refresh on EDEADLK in multistore_file (#336)

## v1.5.1

* Fix bad indent in `tools.run_flow()` (#301, bug was
  introduced when switching from 2 space indents to 4)

## v1.5.0

* Fix (more like clarify) `bytes` / `str` handling in crypto
  methods. (#203, #250, #272)
* Replacing `webapp` with `webapp2` in `oauth2client.appengine` (#217)
* Added optional `state` parameter to
  `step1_get_authorize_url`. (#219 and #222)
* Added `flask_util` module that provides a Flask extension to aid
  with using OAuth2 web server flow. This provides the same functionality
  as the `appengine.webapp2` OAuth2Decorator, but will work with any Flask
  application regardless of hosting environment. (#226, #273)
* Track scopes used on credentials objects (#230)
* Moving docs to [readthedocs.org][1] (#237, #238, #244)
* Removing `old_run` module. Was deprecated July 2, 2013. (#285)
* Avoid proxies when querying for GCE metadata (to check if
  running on GCE) (#114, #293)

[1]: https://readthedocs.org/

## v1.4.12

* Fix OS X flaky test failure (#189).
* Fix broken OpenSSL import (#191).
* Remove `@util.positional` from wrapped request in `Credentials.authorize()`
  (#196, #197).
* Changing pinned dependencies to `>=` (#200, #204).
* Support client authentication using `Authorization` header (#206).
* Clarify environment check in case where GAE imports succeed but GAE services
  aren't available (#208).

## v1.4.11

* Better environment detection with Managed VMs.
* Better OpenSSL detection in exotic environments.

## v1.4.10

* Update the `OpenSSL` check to be less strict about finding `crypto.py` in
  the `OpenSSL` directory.
* `tox` updates for new environment handling in `tox`.

## v1.4.9

* Ensure that the ADC fails if we try to *write* the well-known file to a
  directory that doesn't exist, but not if we try to *read* from one.

## v1.4.8

* Better handling of `body` during token refresh when `body` is a stream.
* Better handling of expired tokens in storage.
* Cleanup around `openSSL` import.
* Allow custom directory for the `well_known_file`.
* Integration tests for python2 and python3. (!!!)
* Stricter file permissions when saving the `well_known_file`.
* Test cleanup around config file locations.

## v1.4.7

* Add support for Google Developer Shell credentials.
* Better handling of filesystem errors in credential refresh.
* python3 fixes
* Add `NO_GCE_CHECK` for skipping GCE detection.
* Better error messages on `InvalidClientSecretsError`.
* Comment cleanup on `run_flow`.

## v1.4.6

* Add utility function to convert PKCS12 key to PEM. (#115)
* Change GCE detection logic. (#93)
* Add a tox env for doc generation.

## v1.4.5

* Set a shorter timeout for an Application Default Credentials issue on some
  networks. (#93, #101)
* Test cleanup, switch from mox to mock. (#103)
* Switch docs to sphinx from epydoc.

## v1.4.4

* Fix a bug in bytes/string encoding of headers.

## v1.4.3

* Big thanks to @dhermes for spotting and fixing a mess in our test setup.

* Fix a serious issue with tests not being run. (#86, #87, #89)
* Start credentials cleanup for single 2LO/3LO call. (#83, #84)
* Clean up stack traces when re-raising in some places. (#79)
* Clean up doc building. (#81, #82)
* Fixed minimum version for `six` dependency. (#75)