Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - [lib.sh] Support older jumpserver libvirt

    `virsh undefine` argument `--nvram` is only supported by newer
    versions of libvirt.
    Although this is mandatory for AArch64, for x86_64 this is not a
    blocker (since we don't enable OVMF for the VMs on the jumpserver).

    Change-Id: I3a82bc54b36228980a41d77a463a7558a685c03d
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index d453485..c415687 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit d453485ff3ddd9602b993a31dc950dc8dc5970d8
+Subproject commit c4156877d3f3f4f7efbca6e129bbeafdbe877d22