find_editor: remove the env_error argument

There is no case where we should fail to find an editor just because
the values of EDITOR, VISUAL and SUDO_EDITOR are unavailable.  Both
sudoedit and the "env_editor" sudoers setting are documented as
falling back on the hard-coded list of editors in the "editors"
sudoers setting.  Bug #1000

plugins/sudoers/regress/editor/check_editor.c

@@ -105,7 +105,7 @@ main(int argc, char *argv[])
 
 	putenv(data->editor_var);
 	editor_path = find_editor(data->nfiles, data->files, &edit_argc,
-	    &edit_argv, NULL, &env_editor, false);
+	    &edit_argv, NULL, &env_editor);
 	ntests++;
 	if (strcmp(editor_path, data->editor_path) != 0) {
 	    sudo_warnx("test %d: editor_path: expected \"%s\", got \"%s\"",