coding mistake in ImageDataSource.scala

[yteric]

caffe-grid/src/main/scala/com/yahoo/ml/caffe/ImageDataSource.scala:121
if (mat.width() != sample_width || mat.height() != sample_width) {
the second sample_width should be sample_height

[junshi15]

Thanks for your comment. We will fix it shortly.

[anfeng]

This issue is closed w/ PR #64