There's a certificate issue in Paho MQTT which should be fixed in
the latest paho.mqtt.testing branch.
Task-number: QTBUG-126364
Change-Id: I1550122939ea8e6172dba005752978fcf3232fcb
Reviewed-by: Jukka Jokiniva <jukka.jokiniva@qt.io>
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>