I've tested the upgrade using the release upgrader tarball from wily proposed and the obsolete kernel detection / removal process looks better.
2015-10-21 15:59:51,435 DEBUG identifyObsoleteKernels() 2015-10-21 15:59:54,727 DEBUG removing obsolete kernel 'linux-headers-3.19.0-15-generic' 2015-10-21 15:59:54,727 DEBUG skipping running kernel linux-headers-3.19.0-30-generic 2015-10-21 15:59:54,728 DEBUG removing obsolete kernel 'linux-image-3.19.0-15-generic' 2015-10-21 15:59:54,728 DEBUG skipping running kernel linux-image-3.19.0-30-generic 2015-10-21 15:59:54,729 DEBUG removing obsolete kernel 'linux-image-extra-3.19.0-15-generic' 2015-10-21 15:59:54,729 DEBUG skipping running kernel linux-image-extra-3.19.0-30-generic 2015-10-21 15:59:56,525 DEBUG identifyObsoleteKernels found '{'linux-image-extra-3.19.0-15-generic', 'linux-image-3.19.0-15-generic', 'linux-headers-3.19.0-15-generic'}'
I've tested the upgrade using the release upgrader tarball from wily proposed and the obsolete kernel detection / removal process looks better.
2015-10-21 15:59:51,435 DEBUG identifyObsolet eKernels( ) headers- 3.19.0- 15-generic' 3.19.0- 30-generic image-3. 19.0-15- generic' 3.19.0- 30-generic image-extra- 3.19.0- 15-generic' extra-3. 19.0-30- generic eKernels found '{'linux- image-extra- 3.19.0- 15-generic' , 'linux- image-3. 19.0-15- generic' , 'linux- headers- 3.19.0- 15-generic' }'
2015-10-21 15:59:54,727 DEBUG removing obsolete kernel 'linux-
2015-10-21 15:59:54,727 DEBUG skipping running kernel linux-headers-
2015-10-21 15:59:54,728 DEBUG removing obsolete kernel 'linux-
2015-10-21 15:59:54,728 DEBUG skipping running kernel linux-image-
2015-10-21 15:59:54,729 DEBUG removing obsolete kernel 'linux-
2015-10-21 15:59:54,729 DEBUG skipping running kernel linux-image-
2015-10-21 15:59:56,525 DEBUG identifyObsolet