increase in minimum deltaiso size during F15 development cycle

[Andre Robatino]

I posted the sizes of the DVD->DVD deltaisos between successive TCs/RCs for the
13, 14, and 15 development cycles at
https://fedorahosted.org/fedora-infrastructure/ticket/2241 . I noted an increase
in the minimum size from about 70 MiB in the 13 and 14 cycles, to about 200 MiB
in the 15 cycle. This is roughly the same as the size of the netinst images. Are
the recent changes in the format of the install images preventing the non-RPM
content of these images from delta-compressing well?