Add integration test for the shell module

##### Issue Type:

“Bugfix Pull Request”

##### Ansible Version:

```
ansible 1.8 (devel bdf3ec1e21) last updated 2014/10/15 11:15:03 (GMT +900)
  lib/ansible/modules/core: (detached HEAD cb69744bce) last updated 2014/10/14 16:45:41 (GMT +900)
  lib/ansible/modules/extras: (detached HEAD 8a4f07eecd) last updated 2014/10/14 16:45:53 (GMT +900)
  v2/ansible/modules/core: (detached HEAD cb69744bce) last updated 2014/10/14 16:46:09 (GMT +900)
  v2/ansible/modules/extras: (detached HEAD 8a4f07eecd) last updated 2014/10/14 16:46:21 (GMT +900)
```

##### Summary:

It adds test for the issue described here: #9272 

Recently, we updated from Ansible 1.4.5 to 1.7.2, and it's no longer working.
As we didn't find any reference to this in the Changelog, we think it's broken and it should be fixed.
After more research, we found it was fixed in a version not yet released.

By adding this test, I hope we will never have this problem again.