export/hazard:
export/hazard:

Made the `export_type` arg of `export` optional, defaulting to 'xml'.
This is so we cause so much disruption to users of this function,
namely QA test code.


Former-commit-id: ac95ab2cc49c1729b99ab8a7d1493e104ad087ba [formerly d4579ff1e52ff3071648caebaa8e741a92d804fc] [formerly d4579ff1e52ff3071648caebaa8e741a92d804fc [formerly 19a8fa4a1eb1fefd590d298567c6d9ea8b2c5cb0]]
Former-commit-id: 28920f9413b10fea44911a461d1f4819f8b53682
Former-commit-id: 7d43aa57b5e3b0043bed9f8315472eae62ec91fe
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine