Fix pipeline use-after-free in AcceptRoutingHandler
Fix pipeline use-after-free in AcceptRoutingHandler

Summary: pipeline->transportActive() could close the pipeline on errors. I think I did
this before ServerConnection() took a shared_ptr pipeline.

Reviewed By: federico

Differential Revision: D2423287

fb-gh-sync-id: 8c825d67538f59a22399a80d86737e8bf8739c7a

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