Chris Willman Music WriterJamie O’Hara, a country music singer-songwriter who came to fame as a member of the O’Kanes, a duo that had six straight top 10 singles in the late 1980s, died Thursday in Nashville. He was 70, and the cause of death was cancer.Besides his tenure with the O’Kanes and subsequent solo work after the duo broke up in 1990, O’Hara was renowned for his solo composition “Grandpa (Tell Me ‘Bout the Good Old Days),” a No.