Fix Drupal resource observer bug and ide creation bug

This fixes two bugs:

1. The Drupal observer should only do stuff if the resources it needs to act on actually exist, previously, it would attempt to do this stuff when creating a Cloud9IDE resource, for example.
2. Some bugs in the creating / deleting of Supervisor resources.

This pull request should be recreated with master as the target, rather than merging this particular one. The order of merges to master should be:

1. TW-95-ssh-conn
2. **fix-bug-cloud9-res**
3. better-loggin
4. caching