Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Take OpenStack's constraints into account"
  - Take OpenStack's constraints into account

    upper-constraints.txt contains a pinned list of the entire set of
    transitive requirements for OpenStack [1].

    We will add OPNFV's constraints as well for OPNFV projects and
    their requirements when they are ready.

    [1] https://specs.openstack.org/openstack/openstack-specs/specs/requirements-management.html

    Change-Id: I2e23584f957e4de191341800d24c8b2776ef9143
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 48db3a5..e6ba406 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 48db3a575a737f957706f58ebdfc1851c3226b63
+Subproject commit e6ba4064cee974284a9ae623ba9de9a40877c59d