add the description to AcceptorException
add the description to AcceptorException

Summary: this description is helpful in debugging.

Reviewed By: viswanathgs

Differential Revision: D2799080

fb-gh-sync-id: 558b497b6e03d6d567933320cbbd3662d2b78d0f

facebook/wangle,jamperry/wangle,Dalzhim/wangle,facebook/wangle,Dalzhim/wangle,facebook/wangle,jamperry/wangle