AthenaCommon: Migrate python code to IOptionsSvc

A few python changes to migrate to the new IOptionsSvc interface:

• Migrate ConfigurationShelve ("drop&reload") to IOptionsSvc.
• Rewrite the JobOptionsUnitTests to work with the new IOptionsSvc interface. At the same time get rid of the now rather useless ServicesPythonize.py, which was only used in this test.
• Also delete unused CfgMergerLib.py.

Running this with all unit tests. So when reviewing this, please compare the unit test failures with the latest nightly.

cc @leggett

added full-unit-tests label

This merge request affects 1 package:

• Control/AthenaCommon

Adding @ssnyder as watcher

added Core master review-pending-level-1 labels

CI Result FAILURE (hash 71bf9276)

	Athena	AthSimulation	AthGeneration	AnalysisBase
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
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 20130]

• Test failures seem to be the same as in the nightlies
• Changes look straight-forward

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

merged

mentioned in commit dcf7517e

added sweep:ignore label