Fix test failure in cmdline.py

Author: antonio-rojas

src/sage/tests/cmdline.py

@@ -302,7 +302,7 @@
     Debugging requires single-threaded operation, setting number of threads to 1.
     Running doctests with ID...
     Doctesting 1 file.
-    sage -t ...
+    ...
     **********************************************************************
     File "...", line 3, in ...
     Failed example: