[model][xs] Cope with sqlite on my machine returns a datetime instead…

… of a string.

ckan/model/types.py

@@ -85,7 +85,7 @@ def iso_date_to_datetime_for_sqlite(datetime_or_iso_date_if_sqlite):
     # to call this to convert it into a datetime type. When running on
     # postgres then you have a datetime anyway, so this function doesn't
     # do anything.
-    if meta.engine_is_sqlite():
+    if meta.engine_is_sqlite() and isinstance(datetime_or_iso_date_if_sqlite, basestring):
         return datetime.datetime.strptime(datetime_or_iso_date_if_sqlite,
                                           '%Y-%m-%d %H:%M:%S.%f')
     else: