rpm/makerpm.sh: add timestamp calculation
rpm/makerpm.sh: add timestamp calculation


Former-commit-id: 0fccd6e9d407157a921eb3b477a945b927e42a43 [formerly a319001d4cf0b98b5c574bea127a3b24e08171d0]
Former-commit-id: 7a55086357c36fbc146726367dedf732409da561
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine