StringKeys → GaudiKernel Relation

File in GaudiTestSuite/src/StringKeys	Includes file in GaudiKernel
StringKeyEx.cpp	include / GaudiKernel / HashMap.h
StringKeyEx.cpp	include / GaudiKernel / Map.h
StringKeyEx.cpp	include / GaudiKernel / StatusCode.h
StringKeyEx.cpp	include / GaudiKernel / StringKey.h