Fix bug in identifying ISO 2022 character set extensions.
Fix bug in identifying ISO 2022 character set extensions.

For example, "\ISO 2022 IR 159" would be correctly identified as
"ISO 2022 IR 159" but "ISO 2022 IR 14\ISO 2022 IR 159" would be
misidentified as "ISO 2022 IR 14".

hendradarwin/vtk-dicom,dgobbi/vtk-dicom,dgobbi/vtk-dicom,hendradarwin/vtk-dicom,hendradarwin/vtk-dicom,dgobbi/vtk-dicom