Removed the flag `split_sources`
Removed the flag `split_sources`


Former-commit-id: b67a7840cafa0c6f70b1ec8e8545cc7cde92e082 [formerly b67a7840cafa0c6f70b1ec8e8545cc7cde92e082 [formerly b02be58df5c7efca47beca28d8d08a2005a39dc8]]
Former-commit-id: 6304e1e96383196da25ebf576a8e09eff6632509
Former-commit-id: 39ba4dd3776dfb9beb913984a3e22599709b6dfe
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine