CA-34933: link sessions and tasks in the datamodel in order to know whether a session is used.
CA-34933: link sessions and tasks in the datamodel in order to know whether a session is used.

Signed-off-by: Thomas Gazagnaire <d17b540e4bd20a6d2c62b93674760725b3f75517@citrix.com>

sharady/xcp-networkd,simonjbeaumont/xcp-rrdd,koushikcgit/xcp-networkd,simonjbeaumont/xcp-rrdd,djs55/xcp-rrdd,koushikcgit/xcp-rrdd,johnelse/xcp-rrdd,koushikcgit/xcp-rrdd,djs55/xcp-rrdd,koushikcgit/xcp-rrdd,robhoes/squeezed,johnelse/xcp-rrdd,djs55/squeezed,sharady/xcp-networkd,djs55/xcp-networkd,djs55/xcp-networkd,koushikcgit/xcp-networkd