AutoPageSeg/FindBlocks/GridRemoveUnderlinePartitions: avoid self-deletion
AutoPageSeg/FindBlocks/GridRemoveUnderlinePartitions: avoid self-deletion

When checking horizontal line partitions for
possible interpretation as underline formatting,
avoid confusing the hline partition itself with
an overlapping neighbour (which would delete it).

tesseract-ocr/tesseract,tesseract-ocr/tesseract,UB-Mannheim/tesseract,UB-Mannheim/tesseract,stweil/tesseract,amitdo/tesseract,tesseract-ocr/tesseract,tesseract-ocr/tesseract,UB-Mannheim/tesseract,UB-Mannheim/tesseract,UB-Mannheim/tesseract,stweil/tesseract,amitdo/tesseract,amitdo/tesseract,amitdo/tesseract,tesseract-ocr/tesseract,amitdo/tesseract,stweil/tesseract,stweil/tesseract,stweil/tesseract