dev: consolidate exit value management
dev: consolidate exit value management

Former-commit-id: a800cf9aa8a40d5b10b9586cc9555a1195d30fe4 [formerly a800cf9aa8a40d5b10b9586cc9555a1195d30fe4 [formerly 514130d1e08b81e8fa5c1c76d094b5183d602e54]]
Former-commit-id: 4c75442105628e23724fb728d7c2c377747441d4
Former-commit-id: 158cb0a4dd201e66cdae3ba21c1724e7c8f619cc
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine