AthExThinning: Get tests working with python 3

• Integer division
• getprocessoutput
• has_key
• print function

This merge request affects 1 package:

• Control/AthenaExamples/AthExThinning

Adding @ssnyder ,@rbianchi as watchers

added Core master review-pending-level-1 labels

CI Result SUCCESS (hash 8a3d3829)

	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 7259]

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

merged

mentioned in commit 8298f81b

added sweep:ignore label