Avoid lock on graph uri update in RdfServiceSparql
What does this pull request do?
Run RdfServiceSparql graph uri update in a separate thread to avoid lock the same way it was previously implemented in RDFServiceJena.
How should this be tested?
Test as in issue description:
- Configure VIVO to use ContentTripleSourceSPARQL
- Try adding/removing graph.
Interested parties
@VIVO-project/vivo-committers @chenejac @brianjlowe