PERF: fix cppcheck issues in itk::ImageRegion

[Modules/Core/Common/include/itkImageRegion.h:184]: (performance) Variable 'same' is reassigned a value before the old one has been used.
[Modules/Core/Common/include/itkImageRegion.h:195]: (performance) Variable 'same' is reassigned a value before the old one has been used.

Change-Id: Ib03a09a37e92216d8a7ed05891eb2a5bd578858d
Merge topic 'same-ImageRegion'

a53f244 PERF: fix cppcheck issues in itk::ImageRegion