Update git submodules

* Update docs/submodules/sfc from branch 'master'
  - Fix cleanup function

    A floating ip remains when executing the clean up function. That floating ip
    belongs to the Tacker VNF and thus we should add that creator to the list

    Change-Id: Ic15574bf93f30a26f81a4944d742307dda4bfe6d
    Signed-off-by: Manuel Buil <mbuil@suse.com>

diff --git a/docs/submodules/sfc b/docs/submodules/sfc
index 74a36db..b3791d8 160000 (submodule)
--- a/docs/submodules/sfc
+++ b/docs/submodules/sfc
@@ -1 +1 @@
-Subproject commit 74a36db25f6fe2b62b41846f27fbf929d270afe5
+Subproject commit b3791d8df2a7666603148e771191e1f6e7f4a784