Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Merge "Add support for different public network netmask"
  - Add support for different public network netmask

     - Remove hardcoded /24 mask

     - Use PDF as source for public network, with reclass params:
       opnfv_net_public, _mask, _gw, _pool_start, _pool_end

     JIRA: FUEL-315

    Change-Id: Idf3a4ed8f63f58fa90d9c1dcb7751ef3b1c9bd36
    Signed-off-by: Guillermo Herrero <guillermo.herrero@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 03e9296..d8cf4a9 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 03e9296cebe0f38f459f7ae225ab7843fc37480e
+Subproject commit d8cf4a9b8fb25af7fed10b8b9e69f70b601ccbce