VIENNA — Nabucco Gas Pipeline International said it pushed back the start of construction of its 7.9 billion euro ($11.5 billion) link to carry Caspian natural gas to Europe to 2013 and start of operations to 2017. “The timeline has changed as a direct result of the changes in the timing for gas supplies in the Caspian and Middle East regions, as announced by potential suppliers,” Nabucco said Friday on its web site. […]