[csvcolumn_to_scurve] Avoid division by zero.

Check whether the value in the "before" column is zero (specifically,
whether the file size in that column is greater than zero since
filesizes are non-negative) before dividing the value in the "after"
column by it.

Author: nate-chandler

utils/dev-scripts/csvcolumn_to_scurve.py

@@ -14,7 +14,10 @@ def get_selected_csv_rows(input_file, before_column, after_column):
         for row in csv.DictReader(input_file):
             before = float(row[before_column])
             after = float(row[after_column])
-            delta = after / before
+            if before > 0:
+                delta = after / before
+            else:
+                delta = 1
             yield delta
 
     def f(input_data):