Comment 34 for bug 1220165

Ok, no partitions from /dev/sda are mounted, and syslog doesn't show anything else referencing it (such as via LVM). So this may actually be a bug in the kernel, since /dev/sda3 is shown in syslog as having been mounted once, and perhaps there's a reference that fails to be released. But I also don't know why the installer is trying to change the partition table anyway, so this probably needs investigation from both ends.