Update git submodules

Update git submodules

* Update docs/submodules/oom.git from branch 'master'
  to b6e666836146077d9062357399f9fb725e752ba1
  - Merge "[COMMON] Use "" instead of {} as a default value to avoid warning"
  - [COMMON] Use "" instead of {} as a default value to avoid warning

    After we upgraded our helm version we started getting below issues
    with emails:

    Warning: Merging destination map for chart 'curator'.
    Overwriting table item 'image', with non table value:
    onap/sdnc-image:1.8.2

    To fix this let's just use "" instead of () for our daily operations.

    Issue-ID: OOM-2412
    Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
    Change-Id: I5f2c215c281036a7eb921d6a805527c807a4aca9