Clean up bkr.server.controller_utilities

- clean up imports
- clean up indentation
- remove unused variable

Change-Id: I8079204ad579592b335cf27acf4f639850e0f16a
Clean up bkr.server.controllers

- clean up imports
- clean up indentation
- remove unused variables

Change-Id: Ia4e2bda5c54fae9484a019fd3e89700dfe6ff0a3
Merge "Clean up bkr.server.controller_utilities" into develop
Merge "Clean up bkr.server.controllers" into develop