Update git submodules

* Update docs/submodules/apex from branch 'master'
  - Merge "Fixes OpenDaylight version"
  - Fixes OpenDaylight version

    The default version is now Carbon with the option of using
    nitrogen (master) for puppet-odl and opendaylight.

    JIRA: APEX-500

    Change-Id: I44d02ec0db5fb8e6342e5ab6802a5a3f302b8511
    Signed-off-by: Tim Rozet <trozet@redhat.com>

diff --git a/docs/submodules/apex b/docs/submodules/apex
index 12e2bf1..16821de 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit 12e2bf17f56d7a83b2779468e543857550f9f68a
+Subproject commit 16821de4807132ab784926e21059d793e36667ce