Comment 5 for bug 258036

Alexander: when you move files between packages, you need to set a Replaces field or dpkg may return an error on upgrades. For example, if a file moves from package foo to package bar and version 1.0-0ubuntu2 is the first version of package foo *not* to contain the file, then package bar should have "Replaces: foo (<< 1.0-0ubuntu2)". See the policy manual for more details.

Could you please update your patch with this change?