Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Remove final ' placed at the end of each line by sed"
  - Remove final ' placed at the end of each line by sed

    I dont think the ' does anything good, as it ends up in the output
    remove extraneous cat

    Change-Id: I4ca62672aa361d370275bd74864f0fc179da9f0b
    Signed-off-by: agardner <agardner@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 6256ecd..6b51b80 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 6256ecdb5ffff289624d94630145c7af13c8378a
+Subproject commit 6b51b809665b325ef4b6c71e4397d9a454ba35c3