Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - [MaaS] Force Maas to use a fixed ip packet size

    Maas uses a tftp library during commisioning which in turn uses another
    library which tries to find the best packet size to use. For some reason
    during commisioning the library uses smaller sizes than the
    infrastructure can handle and therefore takes a lot of time to deploy.

    JIRA: ARMBAND-351

    Change-Id: I9b3083a059c04b118e8b7f0f2723af67d96d2aad
    Signed-off-by: Charalampos Kominos <charalampos.kominos@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 19a10e0..ed8fc8f 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 19a10e0217a17d220d5e9333ff4f1d324b6bf68c
+Subproject commit ed8fc8fe0b2ce8058b8c14e84c4119d93acc6f76