Update git submodules

* Update docs/submodules/releng from branch 'master'
  - vswitchpef: avoid build at ericsson-build3

    VSPERF's VERIFY & MERGE jobs are having issues at ericsson-build3
    since September. The problem is, that after a few successful runs,
    machine starts to be very slow and thus it is not possible to execute
    neither OVS nor VPP anymore. Debugging together with responsible
    admins didn't help to find a root cause (probably a race condition
    during execution of vsperf & other projects). As a temporary measure,
    I want to tight vsperf jobs to ericsson-build4 only, where they work
    without issues.

    Change-Id: I62e482f57234f90fc127b6e6d9454488e17657fc
    Signed-off-by: Martin Klozik <martinx.klozik@intel.com>
    Reviewed-by: Fatih Degirmenci <fatih.degirmenci@ericsson.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 28178b5..d5a589b 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 28178b501d59ff6b3ddbfdbdd947dff7951a6c02
+Subproject commit d5a589b85c6241f757d4d62c42f2cddb1f7dd8b9