[oe] bitbake -c clean doesn't clean all stuff

[Ihar Hrachyshka]

Hello!
'Bitbake -c clean' cleans all staging, work... files but not ipks.
What's the reason for such behaviour?
1) If I clean my recipe I want to be pretty sure build system won't
use any files from the old build process. But it's not. F.e. if I
built '1.1.2' recipe, then removed it and built '1.1.1' I want to be
sure my rootfs uses '1.1.1'. But old-new ipks are in deploy dir, and I
get 1.1.2 in my rootfs.
2) If I built recipe with 'PACKAGES = ${PN}', then cleaned it, edited
my recipe to have "PACKAGES += ${PN}-xxx", and my ${PN} is empty and
OE doesn't generate ipk for it, but old ipk is still there, ready to
be installed to my rootfs through obsolete deps of other recipes! I
don't see the problem until I rebuild my rootfs from scratch.
So my question is: why doesn't OE clean ipks when cleaning?