Merge branch 'jc/name' into next

* jc/name:
  sha1_name: make core.warnambiguousrefs the default.
  sha1_name: warning ambiguous refs.

ls-tree.c

@@ -90,6 +90,7 @@ int main(int argc, const char **argv)
 	struct tree *tree;
 
 	prefix = setup_git_directory();
+	git_config(git_default_config);
 	if (prefix && *prefix)
 		chomp_prefix = strlen(prefix);
 	while (1 < argc && argv[1][0] == '-') {