Only create a new job from binlog when we have a tube name

A READY or DELAYED entry in the binlog only has a tubename when the
job is first created. A release of a job with a delay will insert a new
entry without a tubename.

This fixes a problem when on replay of the binlog a record is
encountered that is modifying an existing job. But that job was originally
created in a prior binlog file that has been deleted becasue all
its jobs have been deleted. ie a modification to a job that has
already completed so we do not need to create it

binlog.c

@@ -180,7 +180,7 @@ binlog_read_one(int fd, job binlog_jobs, const char *path)
  break;
  case JOB_STATE_READY:
  case JOB_STATE_DELAYED:
- if (!j) {
+ if (!j && namelen > 0) {
  t = tube_find_or_make(tubename);
  j = make_job_with_id(js.pri, js.delay, js.ttr, js.body_size,
  t, js.id);