Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Merge "Disable vyos_vrouter" into stable/euphrates
  - Disable vyos_vrouter

    It's postponed to 5.1.

    Change-Id: Ic06d47b4b5df167044363b40aea0c7932b550be7
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
    (cherry picked from commit ef034e78a6a3cfe90da77a60ae88d0d6bfddfb2e)

diff --git a/docs/submodules/functest b/docs/submodules/functest
index f16ba39..e8fab56 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit f16ba39de51b9e6893002a8ea7be1891c35083a3
+Subproject commit e8fab5661697eb17c28fd14ed712ff776c2af39b