Handle session timeout in the VMware store

The current implementation can lead to session timeouts. This
will occur when accessing the datastore directly through HTTP.
This patch provides a retry mechanism by recreating the session
when getting a 401 status code.

Change-Id: I54cc9e30c9bc374a2cf82dec4beb9b06594835f8
Closes-Bug: #1311960
Merge "Handle session timeout in the VMware store"