Update git submodules

* Update docs/submodules/sdnvpn from branch 'stable/fraser'
  - [Bug Fix] Use correct image for the Quagga instance

    In testcase_3 the Quagga image is downloaded from the
    opnfv.artifacts repository to the /home/opnfv/functest/data
    directory.

    But the testcase_3 after that tries to find the image in the
    /home/opnfv/functest/images directory.

    This results in using a wrong image

    Jira: SDNVPN-213

    Change-Id: I99539fc9a7a2d016a97ed51fca0cde81f82b3911
    Signed-off-by: Dimitrios Markou <mardim@intracom-telecom.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index 24106af..e0a0bcc 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit 24106af0bc806b68c2f7b2901638127d9249b8d0
+Subproject commit e0a0bccf7172b8cdd3e0ac2af7c2736b89ef5f75