Remove unused import causing deprecation warning
Remove unused import causing deprecation warning

Warning in the form:
RemovedInDjango19Warning: "ModelXYZ" doesn't declare an explicit app_label
Apparently this happens because it tries to import models before app
configuration runs

shirlei/helios-server,shirlei/helios-server,benadida/helios-server,benadida/helios-server,shirlei/helios-server,benadida/helios-server,benadida/helios-server,shirlei/helios-server,shirlei/helios-server,benadida/helios-server