Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "doctor: workaround for bug of set-functest-env.sh"
  - doctor: workaround for bug of set-functest-env.sh

    `set-functest-env.sh' is expected to run with functest jobs,
    so it need one of the files in functest repo placed under
    WORKSPACE.

    This patch avoiding this bug by getting functest repo in pre
    section of functest trigger.

    Change-Id: Ib266781005bab18f34fa0cdfe50e0facb95d27ef
    Signed-off-by: Ryota MIBU <r-mibu@cq.jp.nec.com>