progress: get the extremely verbose output out of default debug When the progress extension is not enabled, each call to 'ui.progress' used to issue a debug message. This results is a very verbose output and often redundant in tests. Dropping it makes tests less volatile to factor they do not meant to test. We had to alter the sed trick in 'test-rename-merge2.t'. Sed is used to drop all output from a certain point and hidding the progress output remove its anchor. So we anchor on something else.