Update git submodules

* Update docs/submodules/releng from branch 'master'
  - update fraser 6.2.0 release tag for sdnvpn

    Change-Id: Id78fbfe1cb2e0ace44d2e6acf688e4115941a84a
    Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 4d4365f..8e98caa 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 4d4365fbdccc4aa50985e1c12070f7643495b14f
+Subproject commit 8e98caa3db263059fefb41903103e75d7a480d74