Remove redundant global def in bkr.server.assets

Change-Id: I400d55d177cfd4688f24048c59b4ac5ef6c034c9
Updated pylint helpers

Change-Id: I8004abd676751fc01a7a41b7dc1ecde847620b02
Merge "Remove redundant global def in bkr.server.assets" into develop
Merge "Updated pylint helpers" into develop