Fix according to celebi-pkg#21 from original

Author: Pap36

src/google_flight_analysis/flight.py

@@ -124,7 +124,7 @@ def _classify_arg(self, arg):
 
 		elif arg.endswith('CO2') and self._co2 is None:
 			# co2
-			self._co2 = int(arg.split()[0])
+			self._co2 = int(arg.split()[0].replace(',',''))
 		elif arg.endswith('emissions') and self._emissions is None:
 			# emmision
 			emission_val = arg.split()[0]