Issue #2369107 by lussoluca: Update Guzzle to 5.0.3.

composer.lock

core/vendor/composer/installed.json

core/vendor/guzzlehttp/guzzle/CHANGELOG.md

core/vendor/guzzlehttp/guzzle/Makefile

core/vendor/guzzlehttp/guzzle/README.md

core/vendor/guzzlehttp/guzzle/composer.json

core/vendor/guzzlehttp/guzzle/docs/events.rst

core/vendor/guzzlehttp/guzzle/docs/faq.rst

core/vendor/guzzlehttp/guzzle/docs/handlers.rst

core/vendor/guzzlehttp/guzzle/src/ClientInterface.php

...dor/guzzlehttp/guzzle/src/Event/AbstractTransferEvent.php

...ndor/guzzlehttp/guzzle/src/Exception/RequestException.php

core/vendor/guzzlehttp/guzzle/src/Message/Response.php

...endor/guzzlehttp/guzzle/src/Message/ResponseInterface.php

core/vendor/guzzlehttp/guzzle/src/Pool.php

core/vendor/guzzlehttp/guzzle/src/Post/MultipartBody.php

core/vendor/guzzlehttp/guzzle/src/Post/PostBody.php

core/vendor/guzzlehttp/guzzle/src/Query.php

core/vendor/guzzlehttp/guzzle/src/RingBridge.php

core/vendor/guzzlehttp/guzzle/src/Url.php