Update git submodules

* Update docs/submodules/releng from branch 'master'
  - jjb: xci: bifrost-cleanup-job: Fix undefined variable

    Variable 'i' does not exist. It should be 'try_to_rm' instead.

    Change-Id: Ic2aa5a1115715851379e2c7ba5c11699cb8e7407
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 37f9e7e..081b14b 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 37f9e7e794d4f407f1e67a4476d0874e89a7db6c
+Subproject commit 081b14b75aedf715500e652f4a9d47522e00fb01