Update git submodules

* Update docs/submodules/apex from branch 'master'
  - Adds SDN Port variables to overcloudrc

    Functest needs these values to be set in overcloudrc to know which ports
    to query ODL on.

    JIRA: APEX-621

    Change-Id: I41e34efccedc26edd98c6dd3f45e553ea76db195
    Signed-off-by: Tim Rozet <trozet@redhat.com>

diff --git a/docs/submodules/apex b/docs/submodules/apex
index f20730a..6379290 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit f20730a6633a9f910a804d5205fbdbff17e622d0
+Subproject commit 63792906e8681bef2f0e03ee12ea422af53d9c12