Update git submodules

* Update docs/submodules/policy/parent.git from branch 'master'
  to 2f5f116faa66414da147618ba137e6efd394e166
  - Upgrade xstream to 1.4.11.1

    While analyzing drools-pdp, it's mvn clean install works
    fine with this fix locally.

    Also exists in engine repo, its mvn clean install works
    fine with this fix locally.

    distribution repo inherits from engine. also mvn clean install
    works fine with this fix locally.

    Issue-ID: POLICY-2001
    Change-Id: I25bd1f5d459f3ad279f1ce57fa0b153af21ece90
    Signed-off-by: Pamela Dragosh <pdragosh@research.att.com>

diff --git a/docs/submodules/policy/parent.git b/docs/submodules/policy/parent.git
index 12a48ac..2f5f116 160000 (submodule)
--- a/docs/submodules/policy/parent.git
+++ b/docs/submodules/policy/parent.git
@@ -1 +1 @@
-Subproject commit 12a48ac8fa5e4ea8e8fe9e5138b1c4623cec7b15
+Subproject commit 2f5f116faa66414da147618ba137e6efd394e166