Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "Enable deltarpm"
  - Enable deltarpm

    DeltaRPM allows to install only the difference between an old and new
    version of an RPM, as consequence this reduces the network
    consumption in CentOS distros.

    Change-Id: I317fbac44ae5fb6d5293443e755e2b7ddd08c66e
    Signed-off-by: Victor Morales <victor.morales@intel.com>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index e55aa58..37082b6 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit e55aa58f2cf5ec7c2d09d1665f5c04c0d84ff7ca
+Subproject commit 37082b6661e778b9faa9190f26df31538faa9680