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

diff.c

@@ -168,6 +168,11 @@ long parse_algorithm_value(const char *value)
  * never be affected by the setting of diff.renames
  * the user happens to have in the configuration file.
  */
+void init_diff_ui_defaults(void)
+{
+	diff_detect_rename_default = 1;
+}
+
 int git_diff_ui_config(const char *var, const char *value, void *cb)
 {
 	if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {