CliPage: fix "auto-focus after problem"
CliPage: fix "auto-focus after problem"

This should have been part of 18b032d02c2518f30c09727a81a134497933eef1.

The whole point of _problemOccurred is that it should never be set back
to false, thereby stopping the "auto-focus if everything is good" other
than the very first page load.

Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui