Add a missing setjmp() to CCodec_JpegDecoder::v_GetNextLine().
Add a missing setjmp() to CCodec_JpegDecoder::v_GetNextLine().

If jpeg_read_scanlines() ends up calling the error callback, we longjmp
into some undefined state.

BUG=558840
R=thestig@chromium.org, tsepez@chromium.org

Review URL: https://codereview.chromium.org/1463563003 .

DrAlexx/pdfium,DrAlexx/pdfium,andoma/pdfium,andoma/pdfium,DrAlexx/pdfium,DrAlexx/pdfium,andoma/pdfium,andoma/pdfium