Update git submodules

* Update docs/submodules/policy/engine.git from branch 'master'
  to 939cf950022f89aec547d3a6a9f6b9443b7a8a95
  - Improve ONAP-PDP-REST JUnit test case independency

    Handle cleanup of changed system properties and other test-related
    static parameters to prevent unexpected behaviour of other test cases
    that are dependent of the same properties and parameters when order
    of the execution changes

    Add Samsung modification copyrights for changed files

    Fix some loggings and a minor typo in documentation

    Change-Id: Ib6920d6300da79bfc426e4f348b503e3fd6a31ee
    Issue-ID: POLICY-1501
    Signed-off-by: kaihlavi <l.kaihlavirt@partner.samsung.com>

diff --git a/docs/submodules/policy/engine.git b/docs/submodules/policy/engine.git
index df36ba3..939cf95 160000 (submodule)
--- a/docs/submodules/policy/engine.git
+++ b/docs/submodules/policy/engine.git
@@ -1 +1 @@
-Subproject commit df36ba3e64a49419a64e580283b21fce79591b71
+Subproject commit 939cf950022f89aec547d3a6a9f6b9443b7a8a95