Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Enable Doctor testcase

    It upates upper-constraints.txt and thirdparty-requirements.txt as
    doctor-test was renamed to doctor-tests.

    It installs the doctor packages and its requirements via python3.
    Then python_version>='3.0' conditions are added to avoid installing
    them for python2.

    It also calls the new console scripts and modifies the installer
    list supporting it.

    Conflicts:
        upper-constraints.txt

    Co-Authored-By: Cédric Ollivier <cedric.ollivier@orange.com>
    Change-Id: Icd855f4534d9d9591165e99aa0eed6b1030018e0
    Signed-off-by: dongwenjuan <dong.wenjuan@zte.com.cn>
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
    (cherry picked from commit 1e1fba3aa18ebcbff6746586654805a44e88e9fe)