Disabling certificates tests on node v0.8.
Disabling certificates tests on node v0.8.

jdiamond/MQTT.js,mcanthony/MQTT.js,bqevin/MQTT.js,RangerMauve/MQTT.js,AdySan/MQTT.js,wesley1001/MQTT.js,authere/MQTT.js,jaambee/MQTT.js,itavy/MQTT.js