Comment 1 for bug 815860

It turns out that this is a bit of a can of worms:
- the dbus backend code in software-properties is missing (this is fixed now)
- /proc/mounts has
  "/dev/sr0 /media/Ubuntu\04011.04\040amd64 iso9660 ro,nosuid,nodev,relatime,uid=1000,gid=1000,iocharset=utf8,mode=0400,dmode=0500 0 0"
  so apt needs to unescape this
- python-apt does not support AutoDetect mode, this is currently done in cmdline/apt-cdrom.cc