Update git submodules

* Update docs/submodules/apex from branch 'master'
  - Ignore error if network already undefined

    In clean we destroy a network, then undefine it. When running snapshot
    deploy it uses manual virsh bash commands to create the networks and
    other virsh resources. This leaves an admin network which our clean
    eventually tries to delete. However when the libvirt api network destroy
    command is used it is somehow undefining the newtork at the same time.
    Therefore just catch that possible scenario and ignore the failure as
    the network has already been removed.

    Change-Id: Id1d861fbe2a338f0828e78721c09f110030d3a4a
    Signed-off-by: Tim Rozet <trozet@redhat.com>

diff --git a/docs/submodules/apex b/docs/submodules/apex
index b813a49..6cb6b37 160000 (submodule)
--- a/docs/submodules/apex
+++ b/docs/submodules/apex
@@ -1 +1 @@
-Subproject commit b813a4985727ccf98c2dc018a4406c504c0189b3
+Subproject commit 6cb6b372fc0f74daf952e04b9d5712c6930cee42