Update git submodules

* Update docs/submodules/sfc from branch 'stable/fraser'
  - Fix the logging to be compatible with functest

    In order to collect logs from SFC test scenarios running through
    functest framework (mainly for troubleshooting purposes),
    the logging mechanism has been updated accordingly.

    JIRA: SFC-125

    Change-Id: Ide7c32519afa6ece299d0ac1dcb168609a2e3945
    Signed-off-by: Panagiotis Karalis <pkaralis@intracom-telecom.com>

diff --git a/docs/submodules/sfc b/docs/submodules/sfc
index 7f8a775..7d4bbcc 160000 (submodule)
--- a/docs/submodules/sfc
+++ b/docs/submodules/sfc
@@ -1 +1 @@
-Subproject commit 7f8a775dec72e03d6cae2400b7a49d7a097c8957
+Subproject commit 7d4bbcc9fe1819f11c7b757f8c074db488baee4b