An Ohio man received a five-year federal prison sentence yesterday for sending threatening e-mails to a lawyer for the town of Scituate and to the town manager in March 2010. Jeffrey L. Clemens, 49, sent the messages after his first lawsuit against the town stemming from his arrest in 2005 was dismissed, and as the town was moving to quash a second suit that he had filed, court records show. According to an affidavit, he wrote in one message, “You . . . will get what you deserve. Pow! Bang! Splat!’’ Clemens was sentenced in federal court in Boston. He was convicted of sending the e-mails in May.