bug fix preventing people from chosing own metrics in history

rowers/views/analysisviews.py

@@ -4848,6 +4848,8 @@ def history_view_data(request,userid=0):
         typeselect = 'All'
 
     yaxis = request.GET.get('yaxis','duration')
+    if yaxis not in ['duration','rscore','trimp']:
+        yaxis = 'duration'
 
     g_workouts = Workout.objects.filter(
         user=r,