fix zero or blank value in date form ote-bests view

rowers/views.py

@@ -1651,7 +1651,7 @@ def rankings_view(request,theuser=0,
 	deltaform = DeltaDaysForm(request.POST)
 	if deltaform.is_valid():
 	    deltadays = deltaform.cleaned_data['deltadays']
-	    if deltadays != 0:
+	    if deltadays:
 		enddate = timezone.now()
 		startdate = enddate-datetime.timedelta(days=deltadays)
 		if startdate > enddate:
@@ -1662,6 +1662,9 @@ def rankings_view(request,theuser=0,
 		    'startdate': startdate,
 		    'enddate': enddate,
 		    })
+            else:
+                dateform = DateRangeForm()
+                deltaform = DeltaDaysForm()
 
     else:
 	dateform = DateRangeForm(initial={