modules.dockerio: avoid shadowing of logs() func

************* Module salt.modules.dockerio
salt/modules/dockerio.py:1226: [W0621(redefined-outer-name), _create_image_assemble_error_status] Redefining name 'logs' from outer scope (line 417)
Merge pull request #13301 from hulu/docker-shadowing

modules.dockerio: avoid shadowing of logs() func