Running an upgrade from 15.2 > 15.3.

Specifically using an DVD ISO to upgrade,
It looks like the simple solution to modify repo URLs has been to simply remove
all old repos and install repos likely with the $releasever variable.

A consequence of removing all repos entirely is that if the User has any number
of repos with sometimes odd or unusual URI paths, those will all have to be
researched and set up again, or the User has to cancel the upgrade, backup or
otherwise archive the repo list and then run the upgrade again.

Of course, the upgrade repo option other than to remove the repo is impossible,
which is to leave the repo enabled with the 15.2 repo path.

Request for future ISO upgrades is to re-enable the "Disable" option, and
optionally to make the necessary path changes to use $releasever. 
If this request is implemented, maybe a warning should also display that
disabled repos should not be re-enabled without close examination to make sure
the repo exists for the upgraded openSUSE version and verified configured
properly.