Update git submodules

Update git submodules

* Update docs/submodules/snaps from branch 'master'
  - Merge "SNAPS Stack creators can now return SNAPS network creators."
  - SNAPS Stack creators can now return SNAPS network creators.

    As Heat Stacks are responsible for spawning objects in OpenStack,
    the class OpenStackHeatStack which is responsible for applying and
    managing the state of a stack now can retrieve OpenStackNetwork
    objects for the networks created in the stack for clients who would
    like to query the networks and subnets or update them outside of
    Heat.

    JIRA: SNAPS-171

    Change-Id: I9bf0b81d4f7bfeb1b6392f345022c7d9a57d0415
    Signed-off-by: spisarski <s.pisarski@cablelabs.com>