Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 913e09383a46803dcc96da4b52304a6d48421f14
  - Merge "Remove qcow2 once published"
  - Remove qcow2 once published

    Change-Id: I04b49da75846ed1e84a56ae731a19b145855dd7c
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 95998a2..913e093 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 95998a22aaea3f7c744d5f85959974d1ddf91390
+Subproject commit 913e09383a46803dcc96da4b52304a6d48421f14