adding feature to list all backups from a specific instance
Merge pull request #1 from rmyers/backup

Adding backup runner from rmyers. 
Thanks rmeyers!
Adding checks for creating/deleting/restoring backups when it is not completed
Updated the backup runner to use eventlet.green.subprocess

Change-Id: I450fcb2a286a7c0162a3ec743e7235d5879727cf