Merge branch 'mm/diff-renames-default'

The end-user facing Porcelain level commands like "diff" and "log"
now enables the rename detection by default.

* mm/diff-renames-default:
  diff: activate diff.renames by default
  log: introduce init_log_defaults()
  t: add tests for diff.renames (true/false/unset)
  t4001-diff-rename: wrap file creations in a test
  Documentation/diff-config: fix description of diff.renames

builtin/merge.c

@@ -1187,6 +1187,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	else
 		head_commit = lookup_commit_or_die(head_sha1, "HEAD");
 
+	init_diff_ui_defaults();
 	git_config(git_merge_config, NULL);
 
 	if (branch_mergeoptions)