template (filters): don't crash on invalid date in date_fmt

src/tools/common/template.py

@@ -353,6 +353,13 @@ class Renderer(object):
         return value if not current else u"{}_{}".format(value, current)
 
     def _date_fmt(self, timestamp, fmt='short', date_only=False, auto_limit=None, auto_old_fmt=None):
+        try:
+            return self.date_fmt(timestamp, fmt, date_only, auto_limit, auto_old_fmt)
+        except Exception as e:
+            log.warning(_(u"Can't parse date: {msg}").format(msg=e))
+            return timestamp
+
+    def date_fmt(self, timestamp, fmt='short', date_only=False, auto_limit=None, auto_old_fmt=None):
         """format date according to locale
 
         @param timestamp(basestring, int): unix time