[criteria update] Rescue mode

[Petr Schindler]

Because of changes in new anaconda [1] and after short discussion with
Chris Lumens, I propose to delete this alpha criterion:

'The rescue mode of the installer must start successfully and be able to
detect and mount an existing default installation'

Reason (according to Chris): There's been no work done on rescue mode
and it is highly unlikely that it does anything at all right now.

Please, if you have some suggestions or notes reply to this thread. If
there won't be any objections I'll make changes during next week.

Petr Schindler

[1] https://fedoraproject.org/wiki/Features/NewInstallerUI