Update git submodules

Update git submodules

* Update docs/submodules/apex from branch 'master'
  - Merge "Sets baremetal workers to 12"
  - Sets baremetal workers to 12

    There is an issue where in Newton the number of workers (sub processes)
    opened per openstack service scales with the number of logical cores on
    the system.  On servers with large amount of processors this causes the
    cloud to fail after some time due to running out of RAM.  This patch
    will limit the number of worker processes to 12, which is the limit in
    Ocata and onwards.

    JIRA: APEX-410

    Change-Id: I28c4762830c19cd758a0729017f2d4a9ebe372b4
    Signed-off-by: Tim Rozet <trozet@redhat.com>
    Signed-off-by: Feng Pan <fpan@redhat.com>