Set connection and container objects to null to return correct values for errors.

git-svn-id: https://plugins.svn.wordpress.org/rackspace-cloud-files-cdn/trunk@1001448 b8457f37-d9ea-0310-8a92-e5e31aec5664
Pasted code to wrong file. Derp.

git-svn-id: https://plugins.svn.wordpress.org/rackspace-cloud-files-cdn/trunk@1001449 b8457f37-d9ea-0310-8a92-e5e31aec5664