small bug fix get METAR

rowers/views/workoutviews.py

@@ -1798,11 +1798,12 @@ def workout_downloadwind_view(request,id=0,
         windspeed = winddata[0]
         windbearing = winddata[1]
         message = winddata[2]
-        try:
-            row.notes += "\n"+message
-        except TypeError:
-            if message and row.notes:
-                row.notes += message
+        if message is not None:
+            try:
+                row.notes += "\n"+message
+            except TypeError:
+                if message is not None and row.notes is not None:
+                    row.notes += message
                 
         row.save()
         rowdata.add_wind(windspeed,windbearing)