Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Apex: Fix OS credentials fetch

    Now that keystone V3 Identity is only one supported, OOO 'overcloudrc'
    should be used in Queens and later as that contains V3 creds.
    'overcloudrc.v3' will eventually be removed in OOO.

    Note, this was causing tempest_smoke_serial to fail in Apex with Swift
    test cases. This is due to the fact that in Apex we were only setting
    the OS_REGION_NAME in overcloudrc, and functest was using
    overcloudrc.v3. When Tempest does not have the region set it will simply
    look for the first endpoint it can find for that service type, and was
    not using the right keystone endpoint for Apex.

    Change-Id: I154c9e762dfc5ba035f6e108606ecedcfb0d60d2
    Signed-off-by: Tim Rozet <trozet@redhat.com>