Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Merge "Uploading the initial draft of the first VPN test case "
  - Uploading the initial draft of the first VPN test case

    This should be considered in the danube CVP phase as an
    optional test area for OPNFV compliance

    Change-Id: I99494cf2246e1cf079b87414ef1bb34d9b26e6b3
    Co-Authored-By: Tim Irnich <tim.irnich@ericsson.com>
    Signed-off-by: ChristopherPrice <christopher.price@ericsson.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index dac82ae..b878b94 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit dac82ae3cd24b61fc520e8e4d6bc9d98cb49ee54
+Subproject commit b878b9407ecf605eb57a5a1c53c30a0d90da5ca7