rgw: add errno entry for -ENOTEMPTY

currently if master returns an -ENOTEMTPY, we return a -EIO as we dont
have an entry for this

Signed-off-by: Abhishek Lekshmanan <abhishek@suse.com>
(cherry picked from commit 40c3bfe)

src/rgw/rgw_http_errors.h

@@ -153,6 +153,8 @@ static inline int rgw_http_error_to_errno(int http_err)
         return -EACCES;
     case 404:
         return -ENOENT;
+    case 409:
+        return -ENOTEMPTY;
     default:
         return -EIO;
   }