Quality flags fails when using command line acbfe

It seems the quality flag doesn't work when using command line acbfe to resize a .cbz file.

```
$ acbfe -i the-pillow-method.cbz -o out.cbz -q 91 -r "3182x3182>"
ACBF Editor version 1.15 Copyright 2013-2018 Robert Kubik (Pastierovic).
Licensed under the GNU General Public License. https://launchpad.net/acbf
  33% the-pillow-method-2.jpg -> the-pillow-method-2.jpg
Traceback (most recent call last):
  File "/usr/bin/acbfe", line 147, in <module>
    run()
  File "/usr/bin/acbfe", line 139, in run
    window = main.MainWindow(open_path=open_path, output_file=output_file, cmd_options=opts)
  File "/usr/share/acbfe/src/main.py", line 158, in __init__
    self.convert_images(convert_format, convert_quality, resize_geometry, resize_filter, text_layer)
  File "/usr/share/acbfe/src/main.py", line 591, in convert_images
    im.save(out_path, quality=im_quality)
  File "/usr/lib/python2.7/dist-packages/PIL/Image.py", line 1935, in save
    save_handler(self, fp, filename)
  File "/usr/lib/python2.7/dist-packages/PIL/JpegImagePlugin.py", line 642, in _save
    raise ValueError("Invalid quality setting")
ValueError: Invalid quality setting
```

The quality setting works fine if i set -f WEBP, but not with JPG images.