Update git submodules

Update git submodules

* Update docs/submodules/snaps from branch 'master'
  - Updated stack tests to only use an admin user when necessary.

    Changed super test class OSIntegrationTestCase to allow subclasses
    to set the user roles when required. For all heat stack test,
    the user role will always be 'heat_stack_owner'. 'admin' will be
    used for tests requiring this role (i.e. heat template creates
    flavors)

    JIRA: SNAPS-268

    Change-Id: I0ec01cfea6297547a6a158eec8e5c69af6d6c7d7
    Signed-off-by: spisarski <s.pisarski@cablelabs.com>