Update git submodules

Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Enable OVP tests to run on a DPDK-enabled system

    DPDK-enabled NFVIs require support for hugepages which
    in turn is configured by means of extra_specs in flavors.
    Currently, Functest enables hugepage support if the name
    of the scenario contains the substring "ovs".

    Dovetail allows end users to run all tests on DPDK-enabled systems
    and the documentation has been updates accordingly.

    JIRA: DOVETAIL-665

    Change-Id: If4898da168f8b4c69a045ef3b00b8a8862f29b0c
    Signed-off-by: Panagiotis Karalis <pkaralis@intracom-telecom.com>