Replace eof by error in receivers/filters/writers.

Replace eof by error in receivers/filters/writers.

This way it's possible to tell at a later time why
the receiver/filter/writer terminated.

This allows to increase the delay for reconnecting in case
the receiver failed to connect to para_server: Let the receivers
set the error value to -E_RECV_EOF in case a normal end of file
event occurred and check this value when calculating the restart
barrier.