JCLOUDS-283: Don't use bash shopt in the wrapper script

Don't use bash `shopt` in the wrapper script, as some images with a bash shell don't support it. See [JCLOUDS-283](https://issues.apache.org/jira/browse/JCLOUDS-283) for the details about the motivation and the applied changes.

I've tested the change with jclouds-chef (which uses a quite complex wrapped script) and succesfully deployed a Wordpress in EC2 with an Ubuntu AMI (us-east-1/ami-d0f89fb9). The chef bootstrap script makes use of the aliases that have been transformed to a function, so the applied changes shouldn't break existing code.

@zack-shoylev, @everett-toews (or any OpenStack ninja :D) could you try this PR with a `cirrus` image or any other that used to fail?