Issue #2276119 by damiankloip: Upgrade Guzzle to version 4.1.0.

composer.json

composer.lock

core/vendor/composer/ClassLoader.php

core/vendor/composer/autoload_files.php

core/vendor/composer/autoload_real.php

core/vendor/composer/installed.json

core/vendor/guzzlehttp/guzzle/CHANGELOG.md

core/vendor/guzzlehttp/guzzle/README.md

core/vendor/guzzlehttp/guzzle/UPGRADING.md

core/vendor/guzzlehttp/guzzle/composer.json

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

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

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

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

core/vendor/guzzlehttp/guzzle/docs/http-messages.rst

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

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

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

...endor/guzzlehttp/guzzle/src/Adapter/Curl/BatchContext.php

...endor/guzzlehttp/guzzle/src/Adapter/Curl/MultiAdapter.php