Do not coredump if we have an unexpected reply.

If we are speaking to the wrong device, it is very likely we will have an
"unexpected reply" and we should ignore it.

libnfc/chips/pn53x.c

@@ -104,10 +104,6 @@ pn53x_check_ack_frame (nfc_device_t * pnd, const byte_t * pbtRxFrame, const size
   }
   pnd->iLastError = DEACKMISMATCH;
   ERR ("%s", "Unexpected PN53x reply!");
-#if defined(DEBUG)
-  // coredump so that we can have a backtrace about how this code was reached.
-  abort ();
-#endif
   return false;
 }