fix jspm/jspm-cli#519
fix jspm/jspm-cli#519

lookfirst/builder,douglasduteil/builder,tonytanger/builder,synaptek/builder,buddhike/builder,richardTowers/builder,JeroenVinke/builder,systemjs/builder,matthewbauer/builder,whitneyit/builder,Psvensso/builder,robwormald/builder,whitneyit/builder,lookfirst/builder,matthewbauer/builder,alexisvincent/builder,Munter/builder,jrauschenbusch/builder,richardTowers/builder,alexisvincent/builder,alexisvincent/builder,ahmedshuhel/builder,robwormald/builder,Munter/builder,JeroenVinke/builder,jrauschenbusch/builder,ahmedshuhel/builder,systemjs/builder,jrauschenbusch/builder,alexandr2110pro/builder,buddhike/builder,douglasduteil/builder,alexandr2110pro/builder,synaptek/builder,Psvensso/builder,systemjs/builder,tonytanger/builder