Update git submodules

* Update docs/submodules/releng from branch 'master'
  - prototypes: bifrost: Fix Ironic drivers for VMs

    Commit d8235c3c97f4("Set database pool_size in ironic.conf and
    inspector.conf templates") added a copy of the ironic.conf.j2
    template file to workaround an upstream bug but it also changed
    the default ironic drivers leading to broken introspection. We use
    virtual BMC for controlling the VMs and this expects ipmi ironic
    drivers so we fix that.

    Change-Id: Ibb2cc58738ec1693e136bdce7335cd1b861ec613
    Fixes: d8235c3c97f4("Set database pool_size in ironic.conf and inspector.conf templates")
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 1c1ad5e..7c1b8bf 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 1c1ad5e3f5262fa24484c436583468e7e702c566
+Subproject commit 7c1b8bf89d6ce3ec0114c103e6d62161eb12a071