Caffe2 [easy]: Better exception logging in parallel_workers/data_workers
Caffe2 [easy]: Better exception logging in parallel_workers/data_workers

Summary: Instead of printing the exception using print() use traceback.print_exc()  This way you get a stack trace

Reviewed By: jay-mahadeokar

Differential Revision: D5604642

fbshipit-source-id: f8cb67e554305cd2fbed384a4a2040fa2b16e7c0

pietern/caffe2,davinwang/caffe2,xzturn/caffe2,Yangqing/caffe2,sf-wind/caffe2,xzturn/caffe2,davinwang/caffe2,sf-wind/caffe2,Yangqing/caffe2,pietern/caffe2,pietern/caffe2,davinwang/caffe2,pietern/caffe2,xzturn/caffe2,pietern/caffe2,sf-wind/caffe2,davinwang/caffe2,Yangqing/caffe2,sf-wind/caffe2,caffe2/caffe2,sf-wind/caffe2,xzturn/caffe2,davinwang/caffe2,xzturn/caffe2,Yangqing/caffe2,Yangqing/caffe2