STYLE: Declare local `buffer` in `GE5ImageIO::ReadHeader` as unique_ptr
STYLE: Declare local `buffer` in `GE5ImageIO::ReadHeader` as unique_ptr

Fixes potential (however rare) memory leaks, in case of an exception during the
execution of `GE5ImageIO::ReadHeader`.

richardbeare/ITK,Kitware/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,BRAINSia/ITK,Kitware/ITK,richardbeare/ITK,BRAINSia/ITK,BRAINSia/ITK,hjmjohnson/ITK,Kitware/ITK,hjmjohnson/ITK,BRAINSia/ITK,richardbeare/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,Kitware/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,Kitware/ITK,Kitware/ITK,hjmjohnson/ITK,Kitware/ITK,hjmjohnson/ITK,BRAINSia/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,richardbeare/ITK,hjmjohnson/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK