osx.c: try to eliminate invalid free of an uninitialized structure. untabify various drivers and get this more in-sync with gnu_linux.c driver.

lib/driver/os2.c

@@ -1520,6 +1520,7 @@ cdio_open_os2 (const char *psz_orig_source)
     return ret;
   else {
     free_os2 (_data);
+    free(ret);
     return NULL;
   }
 #else