nios-ii-on-die-temperature-sensor example

You can always regenerate the .sopcinfo file. They aren't interchangeable from design to design - the file describes the address map for a Qsys based system to the Eclipse tools. So what you need to do is launch Quartus. Then launch Qsys Tools -> Qsys. Then open the Qsys file (generally in the top directory of where you unpacked the design example). Then hit generate HDL, save and finish. Now you have the .sopcinfo file that correlates to the temperature sensor design that you can load into Eclipse. Best of luck.