removed previous loader_unittest.py file, maintaining db_loader_unittest.py
removed previous loader_unittest.py file, maintaining db_loader_unittest.py


Former-commit-id: c860cc53d22362b3dbf4771cbd6e9c07fdcdf823 [formerly c860cc53d22362b3dbf4771cbd6e9c07fdcdf823 [formerly f26b9344ca68ca127af597417b8f4906c2423a66]]
Former-commit-id: 42e284a122f74149b20d1fb90f5930cc6380eaba
Former-commit-id: 50df279b4007276048fc9db71014bce5b8b6abac
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine