bin/omero: workaround for `python bin/omero` import usage

[joshmoore]

see:

• https://github.com/manics/ansible-role-omero-web/pulls
• https://github.com/ome/omero-server-docker/pull/34

[joshmoore]

Including this in the first 5.6.0-m2 tag. Happy to roll it back in favor of #38 once that's tested.