Fix connection.parse.js test for node-mqtt-packet 7.1.1

[grandpaul]

If we set incorrect flags / qos, node-mqtt-packet 7.1.1 will emit an error exception and thus fail the tests. This commit fixes those failed tests.

Signed-off-by: Ying-Chun Liu (PaulLiu) [email protected]

The test fail log is at https://ci.debian.net/data/autopkgtest/unstable/amd64/n/node-mqtt-connection/17702033/log.gz

Please review this patch and see if it is correct. Thanks.