Use https when submitting user email to pio
Use https when submitting user email to pio

When installing pio using the install.sh script, users that subscribe to
updates submit their email to a direct.prediction.io endpoint using
http. Email is PII and should be transmitted using https.

pferrel/PredictionIO,wangmiao1981/PredictionIO,marevol/incubator-predictionio,wangmiao1981/PredictionIO,mars/incubator-predictionio,takezoe/incubator-predictionio,shimamoto/incubator-predictionio,alex9311/PredictionIO,PredictionIO/PredictionIO,marevol/incubator-predictionio,alex9311/PredictionIO,PredictionIO/PredictionIO,dszeto/incubator-predictionio,takezoe/incubator-predictionio,himanshudhami/PredictionIO,shimamoto/incubator-predictionio,PredictionIO/PredictionIO,mars/incubator-predictionio,pferrel/PredictionIO,dszeto/incubator-predictionio,shimamoto/incubator-predictionio,himanshudhami/PredictionIO,marevol/incubator-predictionio,alex9311/PredictionIO,dszeto/incubator-predictionio,pferrel/PredictionIO,marevol/incubator-predictionio,mars/incubator-predictionio,shimamoto/incubator-predictionio,himanshudhami/PredictionIO,wangmiao1981/PredictionIO,mars/incubator-predictionio,himanshudhami/PredictionIO,dszeto/incubator-predictionio,takezoe/incubator-predictionio,takezoe/incubator-predictionio