Update git submodules

* Update docs/submodules/apex from branch 'master'
  - Disable tripleo_ui

    Change-Id: Ib35bc67d15c306b416801838bba48b7090bff174
    Signed-off-by: Feng Pan <fpan@redhat.com>

diff --git a/docs/submodules/apex b/docs/submodules/apex
index dec6bf3..bf3e6ff 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit dec6bf3f25f340c2523c9f288400499072bfbe94
+Subproject commit bf3e6ff5f6a46f1b0bc9d44f27a305aa4f26c469