Revert "Changed batch bundle size for behat tests"

This reverts commit 3657082733461514d5b9f36d8af7d0b7f2279e00.

Conflicts:
	app/config/config_behat.yml
	src/Pim/Bundle/ImportExportBundle/DependencyInjection/PimImportExportExtension.php
	src/Pim/Bundle/ImportExportBundle/Step/BehatStepFactory.php