pdfrenderer: Fix uninitialized local variables
pdfrenderer: Fix uninitialized local variables

Coverity bug reports:

CID 1270405: Uninitialized scalar variable
CID 1270408: Uninitialized scalar variable
CID 1270409: Uninitialized scalar variable
CID 1270410: Uninitialized scalar variable

Those variables are set conditionally in the while loop
and must keep their values in following iterations, so
they must be declared outside of the loop.

Signed-off-by: Stefan Weil <8d4c780fcfdc41841e5070f4c43da8958ba6aec0@weilnetz.de>

stweil/tesseract,tesseract-ocr/tesseract,stweil/tesseract,UB-Mannheim/tesseract,tesseract-ocr/tesseract,amitdo/tesseract,jbarlow83/tesseract,stweil/tesseract,tesseract-ocr/tesseract,amitdo/tesseract,tesseract-ocr/tesseract,jbarlow83/tesseract,UB-Mannheim/tesseract,UB-Mannheim/tesseract,amitdo/tesseract,UB-Mannheim/tesseract,tesseract-ocr/tesseract,UB-Mannheim/tesseract,jbarlow83/tesseract,jbarlow83/tesseract,stweil/tesseract,jbarlow83/tesseract,amitdo/tesseract,amitdo/tesseract,stweil/tesseract