Update git submodules
* Update docs/submodules/dovetail from branch 'master'
- Update OVP portal docker images for missing package
- The missing futures packages was added in patch:
https://gerrit.opnfv.org/gerrit/#/c/58833/
- The patch above does resolve the issue and has
been valdiated on a development instance.
- The issue was likely introduced in patch
https://gerrit.opnfv.org/gerrit/#/c/56623/
Change-Id: I850947e386024e6b65514bdb518799c359234811
Signed-off-by: Eddie Arrage <eddie.arrage@huawei.com>