Fix S3 unavailable region error
Fix S3 unavailable region error

This is to address this error:

  fatal: [site]: FAILED! => {"changed": false, "failed": true, "msg": "Failed to connect to S3: Region  does not seem to be available for awsmodule boto.s3. If the region definitely exists, you may need to upgrade boto or extend with endpoints_path"}

Commit 0dd58e9 changed the logic so an exception is thrown (by
`connect_to_aws`) before the `s3 is None` check is performed. This
changes the `None` check to a catch so the old logic can compensate.

thaim/ansible,thaim/ansible