Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "bug-fix: do not have permission to execute sudo pip"
  - bug-fix: do not have permission to execute sudo pip

    JIRA: BOTTLENECK-211

    This patch is to fix the bug by adding -H flag to sudo, i.e.,
    sudo -H pip install ...

    Change-Id: Icdb187660cc1e08e134a79592e7454b77576f457
    Signed-off-by: Gabriel Yu <Gabriel.yuyang@huawei.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 2a51732..5ec7838 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 2a51732ab54f286053cf7fc3c84bbac1662317a8
+Subproject commit 5ec7838fe8e98e2333ebe4330f2e5cbe1e0ec482