Update git submodules

* Update docs/submodules/promise from branch 'stable/euphrates'
  - Removed unnecessary logs

    Change-Id: I36e086d442d589535b5b645ef8207a5848c7b654
    Signed-off-by: Bertrand Souville <souville@docomolab-euro.com>
    (cherry picked from commit 6dc47bec9e4e23b744c9d74c4fb4846604e7b808)

diff --git a/docs/submodules/promise b/docs/submodules/promise
index 0a36133..639afda 160000 (submodule)
--- a/docs/submodules/promise
+++ b/docs/submodules/promise
@@ -1 +1 @@
-Subproject commit 0a36133326cfe8836b81780cf0ff42ad4021a20f
+Subproject commit 639afdab3b77466296b501f86f64f17e4c188c10