Update git submodules

Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Merge "Horizon: Fix and reload missing css in Pike"
  - Horizon: Fix and reload missing css in Pike

    The horizon in Pike release is broken due to missing
    the static content. This workaround is to:

    - create a missing symbolic link.
      The link is defined as an alias in the apache configuraion
    - collecting and compressing static assets
    - add single "Default" theme as AVAILABLE_THEMES
    - restart apache2 service
    - apply the workaround to Salt states
     'openstack_ha' and 'openstack_noha'

    JIRA: FUEL-324

    Change-Id: Idd70165f1be8d31967a3ab518323e6f3e8406624
    Signed-off-by: ting wu <ting.wu@enea.com>