Update git submodules

Update git submodules

* Update docs/submodules/snaps from branch 'master'
  - Created domain classes for networks and subnets.

    Created Network and Subnet domain classes so neutron_utils.py functions
    returning these types of objects will not be leaking out implementation
    details as each API version can change these data structures which is now
    being handled by the SNAPS neutron utility.

    JIRA: SNAPS-113

    Change-Id: Id95dd0f8c2618c20a1a73a428abb95686dfa8251
    Signed-off-by: spisarski <s.pisarski@cablelabs.com>