dblatex and backticks inside a listing block

Hi,

When using simple quotes in a listing/code block with dblatex generates some strange quotes you cannot copy/paste as is.
Adding the package 'upquote' in style file preserves correct quotes in code blocs.

Please refer to https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=752455 for more details.

Best,
Joseph