Avoid double-free

As of commit b2e3fd1[1] the `authid.User` is no longer newly allocated,
so we must not free it.

[1] <http://git.php.net/?p=php-src.git;a=commit;h=b2e3fd1e691b1dc82aaaf4150461db97bd5acf4a>

Author: cmb69

ext/com_dotnet/com_com.c

@@ -221,7 +221,6 @@ PHP_FUNCTION(com_create_instance)
 
 	if (server_name) {
 		if (info.pwszName) efree(info.pwszName);
-		if (authid.User) efree(authid.User);
 	}
 
 	efree(moniker);