Update git submodules

* Update docs/submodules/sfc from branch 'stable/euphrates'
  - Modify the vnfd to use the new image

    We moved to a new image for SFs but we have not moved the name of the image
    in the vnfd

    Change-Id: I8f658e1dfcf0de3117845f615eddb8fd5b1e11af
    Signed-off-by: Manuel Buil <mbuil@suse.com>

diff --git a/docs/submodules/sfc b/docs/submodules/sfc
index b4d2cde..93021a9 160000 (submodule)
--- a/docs/submodules/sfc
+++ b/docs/submodules/sfc
@@ -1 +1 @@
-Subproject commit b4d2cde30b7854ed239ac9836748781ce5f3e552
+Subproject commit 93021a983853d260d8e48ba6279c7c45bfe3fe0a