Use the actual Country type instead of the name.

We want other pieces of country information (in particular the short
names). This cleans up a lot of code anyway.

As an added bonus, this now catches squadrons that used invalid names
which would previously be passed through to pydcs and... then I don't
know what would happen.

qt_ui/windows/mission/flight/QFlightCreator.py

@@ -40,7 +40,6 @@ class QFlightCreator(QDialog):
         self.game = game
         self.package = package
         self.custom_name_text = None
-        self.country = self.game.blue.country_name
 
         # Make dialog modal to prevent background windows to close unexpectedly.
         self.setModal(True)
@@ -183,7 +182,6 @@ class QFlightCreator(QDialog):
 
         flight = Flight(
             self.package,
-            self.country,
             squadron,
             # A bit of a hack to work around the old API. Not actually relevant because
             # the roster is passed explicitly. Needs a refactor.