Update git submodules

Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "Pin os_heat role to the version with working policy"
  - Pin os_heat role to the version with working policy

    Upstream change modifying policy.json results in failures with
    several heat test case failures with functest healthcheck.

    https://review.openstack.org/#/c/526306/

    Using the policy.json from the earlier commit seems to solve
    the failures which is this

    https://git.openstack.org/cgit/openstack/openstack-ansible-os_heat/commit/?id=0b3eb9348d55d6b1cf077a2c45b297f9a1be730d

    Change-Id: Iaac0911e73743d1b628cc8d4abe460a0a2a66a84
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>