Fix fulltext indexing for binaries when multiple indexes are defined

Configure several indexes that will index blobs

  <index name="global">
    <field>dc:title</field>
    <field>dc:description</field>
    <fieldType>blob</fieldType>
  </index>
  <index name="specific">
    <fieldType>blob</fieldType>
  </index>

Only the global index will be filled.

After the first FulltextUpdaterWork is run, the jobId is reset and then no document will match the jobId used to create the work. As a consequence the other indexes will not be updated.