konsole: non-existent default profile possible

[Aleksey Midenkov <midenok+kde@xxxxxxxxx>]

Somehow my sole profile lost default property and konsole started to display strange colors. Fixed by clicking Set default on the profile, but it took some time to find out what's going on. There should be no possibility for non-existing (non-visible) default profile, it must always be from the list of shown profiles.