Revert "adding check for sites/default/settings.php before checking it out so deploy does not fail on first pantheon deploy before sites/default/settings.php exists"

This reverts commit 257dc1b378a68c30c8e43e716df6dec1872b06df.

This causes future deploys to fail because TEMP_BUILD that replaces Drupal site cloned from Pantheon does not have a settings.php file.