warning to deltaiso users running Rawhide

[Andre Robatino]

A version of xz (4.999.9-0.3.beta.212.gacbc.fc15) which compresses differently
from the versions in F11 to F14 was recently pushed to Rawhide. This has the
side effect of making existing deltaisos not work properly if the newer version
of xz is installed. (At the end of running applydeltaiso, one would get an
"md5sum mismatch, iso is corrupt" error, and the ISO would be unusable.) For
Rawhide users, to use a deltaiso between versions <= 14, do the following:

1) temporarily downgrade all xz-\* packages to the F14 versions (currently
4.999.9-0.2.beta.20100401git.fc14) which are available in
http://download.fedoraproject.org/pub/fedora/linux/development/14/{i386,
x86_64}/os/Packages/. I suggest saving the necessary RPMs in one's home
directory to make switching easy.

2) Run applydeltaiso as usual. If you get an "iso successfully re-created"
message at the end then all is well.

3) Restore the original xz-\* packages (which are necessary for Rawhide's drpms
to rebuild properly when updating).

The xz developer says that the new version of xz will not be pushed to F14 and
below (see https://bugzilla.redhat.com/show_bug.cgi?id=644046 ). I still need to
update the deltaiso documentation at https://fedoraproject.org/wiki/Delta_ISOs
and https://fedoraproject.org/wiki/User:Robatino/Downloads . I don't know yet
exactly how this will affect deltaisos after F14 Final.