The Italian drinks producer Campari is to close two of its factories, the company said yesterday, one in Sesto San Giovanni and other in Termoli.   The site at Sesto San Giovanni was established in 1904 and has some 160 employees while about 30 employees work in the factory at Tremoli. Workers from the Sesto San Giovanni plant are to go on a two-hour strike. However, Campari also said it will construct a new plant at Novi Ligure.