StoreGate+ControlTest: Remove StoreGateSvc::readUniquePrivateCopy.

Deprecated method; not used any more.

This merge request affects 2 packages:

• AtlasTest/ControlTest
• Control/StoreGate

Affected files list will not be printed in this case

Adding @ssnyder as watcher

added Core Test master review-pending-level-1 labels

CI Result SUCCESS (hash 670bd87a)

	Athena	AthSimulation	AthGeneration	AthAnalysis
externals
cmake
make
tests

Full details available on this CI monitor view. Check the JIRA CI status board for known problems
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AthAnalysis: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 64763]

lgtm

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

added review-approved-tier0 label

added review-approved-point1 label

merged

mentioned in commit a06ce57f

added sweep:ignore label