Update git submodules

Update git submodules

* Update docs/submodules/oom/offline-installer.git from branch 'master'
  to 6f6a8122eecccd9d821b75cf96c02b53455838b1
  - Merge "Adding script for autocollection of docker images"
  - Adding script for autocollection of docker images

    This script is collecting docker images from oom based on enabled
    subsystems to specified list

    There are missing images downloaded in run time based on blueprints and
    images necessary for rancher

    Issue-ID: OOM-1678

    Change-Id: I4367a8a7c755bbf6045ad192bbfc4dd68daa92f8
    Signed-off-by: Tomáš Levora <t.levora@partner.samsung.com>