[PIO-72] Add JDBC JARs when they are present
[PIO-72] Add JDBC JARs when they are present

dszeto/incubator-predictionio,marevol/incubator-predictionio,dszeto/incubator-predictionio,shimamoto/incubator-predictionio,mars/incubator-predictionio,takezoe/incubator-predictionio,mars/incubator-predictionio,takezoe/incubator-predictionio,shimamoto/incubator-predictionio,dszeto/incubator-predictionio,marevol/incubator-predictionio,marevol/incubator-predictionio,takezoe/incubator-predictionio,marevol/incubator-predictionio,PredictionIO/PredictionIO,PredictionIO/PredictionIO,PredictionIO/PredictionIO,mars/incubator-predictionio,shimamoto/incubator-predictionio,shimamoto/incubator-predictionio,takezoe/incubator-predictionio,mars/incubator-predictionio,dszeto/incubator-predictionio