Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Merge "Replace cinder client calls with openstack sdk"
  - Replace cinder client calls with openstack sdk

    JIRA: SDNVPN-220

    This patch replaces all calls of cinder client with openstack sdk.

    Change-Id: Iee73a33ee6c2d87236c6bad3ea6a4ca7b100ced0
    Signed-off-by: Stamatis Katsaounis <mokats@intracom-telecom.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index ebf6885..9c5b191 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit ebf6885a907379083b360ae729f69151c1dd8115
+Subproject commit 9c5b191165018cd43f7acb076903619f4681ce23