Update git submodules

Update git submodules

* Update docs/submodules/snaps from branch 'master'
  - Ensure creators' constructors cannot raise exceptions.

    While creating unit tests for vPing that is using SNAPS, exceptions can
    be raised when retrieving their respective OpenStack clients with
    incorrect credentials. Moved client retrieval to the create() method
    which one should expect exceptions to be raised.

    JIRA: SNAPS-81

    Change-Id: Id8e4279f60b97704b25a89c6312dcf2ebdc3f459
    Signed-off-by: spisarski <s.pisarski@cablelabs.com>