ppu: don't do run a full ppudump while only looking for PPU file version

diffoscope/comparators/ppu.py

@@ -66,7 +66,7 @@ class PpuFile(File):
             ppu_version = f.read(3).decode('ascii', errors='ignore')
         if not hasattr(PpuFile, 'ppu_version'):
             try:
-                subprocess.check_output(['ppudump', file.path], shell=False, stderr=subprocess.STDOUT)
+                subprocess.check_output(['ppudump', '-vh', file.path], shell=False, stderr=subprocess.STDOUT)
                 PpuFile.ppu_version = ppu_version
             except subprocess.CalledProcessError as e:
                 error = e.output.decode('utf-8', errors='ignore')