* GDF raises Jirau dam stake to 60 pct from 50.1 pct * Main builder Camargo Correa sells stake as planned * Dam expected to start operations in Jan. 2013 SAO PAULO, Oct 1 (Reuters) - French energy company GDF Suez Group is raising its stake in Brazil's Jirau hydroelectric dam to 60 percent from 50.1 percent, as the project's main builder Camargo Correa sells its ownership stake. The consolidation of ownership, combined with a 2.3 billion real ($1.13 billion) loan announced by s