Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Rename arm-pod3-2 to arm-pod4"
  - Rename arm-pod3-2 to arm-pod4

    Arm-pod3-2 is a second jenkins slave for arm-pod3.
    This slave is arm while the old jenkins slave is x86.
    Fatih requested for this slave to be renamed to arm-pod4
    instead of arm-pod3-2, even if it's a slave for an existing pod

    JIRA: ARMBAND-252

    Change-Id: I5645edd7d774f763e5e72115851c7061bfafd344
    Signed-off-by: Cristina Pauna <cristina.pauna@enea.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 860c4d1..3784cb0 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 860c4d14afacf267139a020907d1a804ee62c4e7
+Subproject commit 3784cb0706bbb8b26c215822779e71f8f67a8a60