Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "modify the parameter of PPA_REPO"
  - modify the parameter of PPA_REPO

    We move the master ppa from <http://205.177.226.237:9999> to
    <http://205.177.226.237:9999/master>. When we build the master iso,
    we need download the ppa from <http://205.177.226.237:9999/master>.

    Change-Id: I5fea8e6c6647f8bc0e550a39a9a4001196216685
    Signed-off-by: wutianwei <wutianwei1@huawei.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index bb8bda1..e5b9b0e 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit bb8bda1d99551746003796f7393316f802644797
+Subproject commit e5b9b0e8f136df251d75a8b147d4546f88795d54