git: ignore "dubious ownership" check

# as www-data
$ git rev-parse HEAD
fatal: detected dubious ownership in repository at "/home/cweiske/dev/gamestick/pjgsapi"
To add an exception for this directory, call:
        git config --global --add safe.directory /home/cweiske/dev/gamestick/pjgsapi
 
$ git -c safe.directory="*" rev-parse HEAD
49aae1568b005e1acf39ce9062db50c622c9a92a