Don't try to be clever about when to emit the currentChanged() signal.

Task-number: https://projects.maemo.org/bugzilla/show_bug.cgi?id=192729
Reviewed-by: kh1

The device configuration widget is now the only place the user
ever has to specify ports.

This subtle bug would lead to weird behavior of QComboBox on Windows.

Reviewed-by: kh1

This is necessary in case there is no run configuration (e.g. for
library projects).