Remove unnecessary check for writable output dir.

os-config-applier is useful by non-root users who have access to
write the files they need to in sub-directories under the main output
directory.

Change-Id: I52af0bd076f3fef99ea09a3074f0b0d5b7e9afca

os_config_applier/os_config_applier.py

@@ -189,9 +189,6 @@ def main(argv=sys.argv):
         if opts.key:
             print_key(opts.metadata, opts.key, opts.type)
         else:
-            if not os.access(opts.output, os.W_OK):
-                raise ConfigException(
-                    "you don't have permission to write to '%s'" % opts.output)
             install_config(opts.metadata, opts.templates, opts.output,
                            opts.validate, opts.subhash)
             logger.info("success")