Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - xci: Restore the OPNFV_SCENARIO variable

    The variable was accidentally removed in ab3c9ad0f9a4 so bring it back.

    Change-Id: I48e4b8dd68969c8e5336e5e571a73f037fb65988
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 7d4a619..304a45b 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 7d4a6198c273aa42f94f6510ca7728f8ff047f1d
+Subproject commit 304a45bbdc52aa5e7f4374d027e4e17f42d2cd75