* Prevent leaking collectors when HPA gets updated
This fixes an issue where collectors would be leaking when HPAs are
getting updated.
Fix this by stopping the collector started for the previous version of
the HPA.
Signed-off-by: Mikkel Oscar Lyderik Larsen <mikkel.larsen@zalando.de>
* Add tests to verify old collector is removed
Signed-off-by: Mikkel Oscar Lyderik Larsen <mikkel.larsen@zalando.de>