By Alexandra Alper SAN JOSE (Reuters) – A left-leaning former diplomat edged ahead in Costa Rica’s presidential election on Sunday, riding a wave of disgust at government corruption to get within reach of wresting power from the centrist government in an April run-off. Luis Guillermo Solis, an academic who has never been elected to office, had a slim lead over ruling party candidate Johnny Araya despite trailing in pre-election polls and early vote returns. Araya was seen as the front-runner ahead of the vote, but his campaign was hurt by corruption scandals that plagued President Laura Chinchilla’s administration.