changes file issue when packaging for backports

[quidame <quidame@Safe-mail.net>]

Hi,

I try to backport bilibop_0.4.22 source package (native). If only changes
from 0.4.22 to 0.4.22~bpo70+1 are copied in to the changes file, lintian
complains with the 'backports-changes-missing' error tag [1]. If I add
-v0.4.21 dpkg-genchanges, the resulting changes file says:

Priority: medium
[...]
Closes: 750507 756086

This overrides the priority of thr bpo package (low, in wheezy-backports);
medium is the priority of 0.4.22 in unstable. It claims to close two bugs
that are already closed in 0.4.22; more, one of these bugs id specific to
jessie/sid, and the bugfix is reverted in the bpo. should I edit the changes
file to modify Priority: field and modify or remove Closes: field ? Or replave
-v0.4.21 option by something more relevant (shortened changelog entry
for 0.4.22) ? Or can I let it go 'as is' ?

Cheers,
quidame 

[1] https://lintian.debian.org/tags/backports-changes-missing.html