The patch file contains the fix. Let me extract just the patch content in the proper unified diff format:

--- a/django/utils/http.py
+++ b/django/utils/http.py
@@ -176,10 +176,11 @@ def parse_http_date(date):
         raise ValueError("%r is not a valid date" % date)
     try:
         year = int(m.group('year'))
-        if year < 100:
-            if year < 70:
-                year += 2000
-            else:
-                year += 1900
+        if year < 100:
+            current_year = datetime.datetime.utcnow().year
+            year += 100 * (current_year // 100)
+            if year > current_year + 50:
+                year -= 100
         month = MONTHS.index(m.group('mon').lower()) + 1
         day = int(m.group('day'))
         hour = int(m.group('hour'))