Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - [bugfix]invalid user ‘jenkins’

    See https://build.opnfv.org/ci/job/fuel-deploy-zte-pod1-daily-master/456/console
    In lib.sh, generate_ssh_key() assumes that "jenkins" is
    the current user name. But on zte-pod1, the ci user name
    isn't jenkins. It is better to use $USER replaced "jenkins".

    JIRA:FUEL-273

    Change-Id: I6ec6847eccd055b8b4062dd202f8f0a24ba6dd73
    Signed-off-by: zhihui wu <wu.zhihui1@zte.com.cn>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index b0600fd..5c3b0e9 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit b0600fd02696e49ce9b5e8baf646914aae70092d
+Subproject commit 5c3b0e9a51e3486ae660685a3c33aed0e39c5ab2