smoketests/simplecase: ported gmpe logic tree to the new syntax
smoketests/simplecase: ported gmpe logic tree to the new syntax


Former-commit-id: 6d4093e9b753cda90cd2b4cc10d86e29f6563ad8
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine