pep8 changes just for dashboard_app/models.py
pep8 changes just for dashboard_app/models.py

Change-Id: Ib4813ae43e153dcc6118cad7fa490ad382a241c9

OSSystems/lava-server,Linaro/lava-server,Linaro/lava-server,Linaro/lava-server,OSSystems/lava-server,Linaro/lava-server,OSSystems/lava-server