Update git submodules

* Update docs/submodules/sfc from branch 'master'
  - Replace artifacts.opnfv links by docs.opnfv links

    artifacts.opnfv is not used anymore. We are using now docs.opnfv

    Apart from that, I removed the OVS-NSH workaround explanation as we don't use
    it anymore

    Change-Id: Iaf4f2d97a4252754f5b22709aef653fff0777eae
    Signed-off-by: Manuel Buil <mbuil@suse.com>

diff --git a/docs/submodules/sfc b/docs/submodules/sfc
index 0a9106c..e0f569c 160000 (submodule)
--- a/docs/submodules/sfc
+++ b/docs/submodules/sfc
@@ -1 +1 @@
-Subproject commit 0a9106c39f131a1d2952e1187ee1d1924d84e1f6
+Subproject commit e0f569cd2146951f33207141df4576bf98cd5769