adding try except in comparison chart

rowers/views.py

@@ -9592,7 +9592,12 @@ def workout_getstravaworkout_view(request,stravaid):
 @login_required()
 def workout_getrunkeeperworkout_view(request,runkeeperid):
     res = runkeeperstuff.get_runkeeper_workout(request.user,runkeeperid)
-    data = res.json()
+    try:
+        data = res.json()
+    except ValueError:
+        messages.error(request,'Error getting workout from Runkeeper')
+        url = reverse(workout_runkeeperimport_view)
+        return HttpResponseRedirect(url)
 
     id,message = add_workout_from_runkeeperdata(request.user,runkeeperid,data)
     w = Workout.objects.get(id=id)