ghostscript, qpdf: Restore API backward compatibility

ocrmypdf/exec/ghostscript.py

@@ -86,8 +86,8 @@ def rasterize_pdf(input_file, output_file, xres, yres, raster_device, log,
             raise SubprocessOutputError()
 
 
-def generate_pdfa(*, pdf_version, pdf_pages, output_file, compression, log,
-                  threads=1):
+def generate_pdfa(pdf_pages, output_file, compression, log,
+                  threads=1, pdf_version='1.5'):
     compression_args = []
     if compression == 'jpeg':
         compression_args = [
@@ -115,8 +115,8 @@ def generate_pdfa(*, pdf_version, pdf_pages, output_file, compression, log,
             "-dQUIET",
             "-dBATCH",
             "-dNOPAUSE",
-            '-dCompatibilityLevel=' + str(pdf_version),
-            '-dNumRenderingThreads=' + str(threads),
+            "-dCompatibilityLevel=" + str(pdf_version),
+            "-dNumRenderingThreads=" + str(threads),
             "-sDEVICE=pdfwrite",
             "-dAutoRotatePages=/None",
             "-sColorConversionStrategy=/RGB",