AthContainers: Fix double-thinning bug.

Do not implement old-style thinning in copyThinned for DataVector. That's already done by ThinningSvc; doing it here will cause containers to be thinned twice.

This merge request affects 1 package:

• Control/AthContainers

Adding @ssnyder ,@rbianchi as watchers

added Core master review-pending-level-1 labels

CI Result SUCCESS (hash 7264f1fc)

	Athena	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 4809]

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit d64769d2

added sweep:ignore label