Update git submodules

Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to 5df2935557f13e9ea42d9e20d0cef6bf5f06acda
  - Merge "Added null check to heatStack.getOutputs() to prevent crash at get() call; removed redundant null check to simplify the code"
  - Added null check to heatStack.getOutputs()
    to prevent crash at get() call; removed redundant
    null check to simplify the code

    Issue-ID: SO-1841
    Signed-off-by: Oleksandr Moliavko <o.moliavko@samsung.com>
    Change-Id: If9d8dcba3008cd7ebe60c17c08c71a07a6df9df4