Update git submodules

* Update docs/submodules/fuel from branch 'stable/danube'
  - Update kvm4nfv commit id

    This kvm4nfv commit includes changes for the config file which disable
    vt-d by default and has the x2apic enabled.

    Conflicts:
    	build/f_isoroot/f_kvm-pluginbuild/config.mk

    Change-Id: I2e8085792fb8222dfc59d4ece0ac58ec9a16c1bd
    Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
    (cherry picked from commit 78c835c56466726e8c5a99942d5179714907b5f4)

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index e14f155..040614e 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit e14f155b82b0fcd695606e785966d27af7b9e3de
+Subproject commit 040614e651db4236e303d02eb9516f8648a74cf9