checkout submodules on aktualizr-app image build
checkout submodules on aktualizr-app image build

Signed-off-by: Robert Danitz <f67b416f1bf9131196623c898e8b296f44680d2c@here.com>

advancedtelematic/aktualizr,advancedtelematic/aktualizr,advancedtelematic/aktualizr,advancedtelematic/aktualizr