remove superfluous empty destructors
remove superfluous empty destructors

The removed definitions do nothing; these classes already have virtual
destructors inherited from their respective base classes.

tackgeun/caffe,gnina/gnina,CZCV/s-dilation-caffe,tackgeun/caffe,wangg12/caffe,gnina/gnina,tackgeun/caffe,tackgeun/caffe,gnina/gnina,wangg12/caffe,CZCV/s-dilation-caffe,gnina/gnina,gogartom/caffe-textmaps,CZCV/s-dilation-caffe,wangg12/caffe,gogartom/caffe-textmaps,gogartom/caffe-textmaps,longjon/caffe,longjon/caffe,longjon/caffe,gogartom/caffe-textmaps,longjon/caffe,wangg12/caffe,gnina/gnina,CZCV/s-dilation-caffe,gnina/gnina