If the package is marked for removal, keep it marked for
removal and do not mark it for keep. If we mark it for keep,
we some how later get to a different stage where it is marked
for unpack instead of removal.
In the example in the bug report, we would get a:
SmartUnPack maas-region-controller-min:amd64 (replace version 2.0.0~alpha3+bzr4810-0ubuntu1 with Segmentation fault
maas-region-controller-min:amd64 was marked for removal, but
we changed it to keep and somehow it thinks that this is to
be replaced now instead of removed (probably because the
InstallVer != CandidateVer [with InstallVer = 0]).
This fixes a regression introduced in release 1.2.7, commit:
Reported-by: LaMont Jones on IRC