Update git submodules

* Update docs/submodules/sdnvpn from branch 'stable/euphrates'
  - Gather logs only if fuel or apex installer

    Change-Id: I11988ad86a916d1d7251aacf951c6362fda961ba
    Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>
    (cherry picked from commit 308dc9989bce115b615fa13ff1dc44080e3a731e)

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index e9ade96..55ed0c7 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit e9ade965ab40c3321b4aab03104e7e211af73d0a
+Subproject commit 55ed0c7bf86effb047d7d64a33cac8dd9d8490ab