Fix dupliated words issue like " by by which"
This is to fix the duplicated words issue like
"The name of key by by which".
@@ -252,7 +252,7 @@ def image_list_detailed(request, marker=None, sort_dir='desc',
:param sort_key:
- The name of key by by which the resulting image list throughout all
+ The name of key by which the resulting image list throughout all
pages (if pagination is enabled) will be sorted. Defaults to
'created_at'.
