ROUND ROCK, Texas — The suspect in a series of bombing attacks in Austin blew himself up early Wednesday as authorities closed in, a dramatic end to a weekslong siege of the Texas capital, where two were killed and four injured in a series of blasts.Authorities had zeroed in on the suspect in the last 24 to 36 hours and located his vehicle at a hotel on Interstate 35 in the Austin suburb of Round Rock, Austin Police Chief Brian Manley said at a news conference.