Update git submodules

* Update docs/submodules/snaps from branch 'stable/euphrates'
  - Set git-review defaultbranch

    Else git-review could rebase euphrates on top of master.

    Change-Id: Ic533a4144db75c540324ace6e6a6279e859984e0
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/snaps b/docs/submodules/snaps
index 019dc36..7b65c59 160000 (submodule)
--- a/docs/submodules/snaps
+++ b/docs/submodules/snaps
@@ -1 +1 @@
-Subproject commit 019dc3609a1e33eaa4cc07367502cfc140e099b7
+Subproject commit 7b65c59d39c3cc61973b212fd247d27ca13f7d63