SAN DIEGO, Jan 26 (Reuters) - Defending champion Brandt Snedeker had to endure a marathon day of putting practice and waiting around at the Farmers Insurance Open on Saturday before play was finally abandoned because of thick fog. The fast-talking American, who trails tournament leader Tiger Woods by seven shots, arrived at the course at 5:30 a.m. local (1330 GMT) for a scheduled tee time at 7:40 a.m., and left at around 4 p.m. without hitting a single competitive stroke after only five minutes of third-round action was possible. ...