Bug#825121: changed severity

[Daniel Pocock]

Based on that feedback, I've raised the severity again, but I won't have
time to start trying to code a solution for at least another 2 or 3
weeks, has anybody seen any code in any other preinst / postinst that
can be copied for this purpose?

If anybody else wants to try uploading a fix for this it would be very
welcome, please just put a note in the bug if you start working on it.