Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Clean requirements.txt

    It removes all requirements which are not detected by pipreqs [1]
    except:
      - robotframework-httplibrary
      - robotframework-requests==0.4.7
      - robotframework-sshlibrary==2.1.3

    They seem indirectly required for the next ODL suites: old_netvirt
    and fds.

    It also defines pbr as requirement and orders dnspython3 conditions.

    [1] https://github.com/bndr/pipreqs

    Change-Id: Idcd01296e5a5862ff8528dc083468b5c4905c9f9
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 997969d..3f46c18 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 997969d3d79bcebf13aeae8763b2c9747df03702
+Subproject commit 3f46c1858ccfc08dc6b5a5a5ce123f2f3fcf2234