_getdns_context_write_priv_file may call fclose twice

[mistr]

In the function _getdns_context_write_priv_file, after the failure of rename, fclose(f) will be called a second time. You should reset the f and fd variables.

	else if (fclose(f))
		_getdns_log(&context->log
		           , GETDNS_LOG_SYS_ANCHOR, GETDNS_LOG_ERR
		           , "Error closing temporary file \"%s\": %s (%p)\n"
			    , tmpfn, _getdns_fileerrnostr(), f);

	else if (rename(tmpfn, path) < 0) {
        f = NULL;
        fd = -1;
		_getdns_log(&context->log
		           , GETDNS_LOG_SYS_ANCHOR, GETDNS_LOG_ERR
		           , "Error renaming temporary file \"%s\" to \"%s\""
			     ": %s\n", tmpfn, path, _getdns_fileerrnostr());
    }
	else {
		context->can_write_appdata = PROP_ABLE;
		return 1;
	}
	if (f)
		(void) fclose(f);

	else if (fd >= 0)
		(void) close(fd);