Pie chart data labels issue after drillup

[PaulDalek]

Behaviour

After a drillup, previously hidden data labels along with their connectors are visible and some of them overlap another. The latest version where issue does not occur is v4.2.7. Probably connected with #4937.

Live demos with steps to reproduce

http://jsfiddle.net/hmsjr4j2/ - newest version (v5.0.6) - issue occurs
http://jsfiddle.net/hmsjr4j2/1/ - v4.2.7 - issue does not occur

1. Drilldown to any series.
2. Drillup back to the main series.
3. Notice additional data labels and theirs connectors.