Implement object expirer feature for gluster-swift for swiftonfile

This blueprint is to track the Object Expiration feature with Gluster for Swift. This is to track the code changes required and see if it can leverage multiple accounts per volume feature of the SWAuth.

Support Client residing outside domain for SwiftKerbAuth

Currently, the client sends a Kerberos TGT received from Kerberos Server. In this case, the client has to be part of Kerberos domain. To support client residing outside domain, we need code changes for: - gleaning account, user and key from request - running kinit against the username and password