Pitbull, Matthew Morrison, Selena Gomez, Far East Movement and others filled the Staples Center on Saturday night. By Matt Elias Britney Spears hosts KIIS FM’s Wango Tango 2011 on Saturday Photo: Kevin Winter/ Getty Images LOS ANGELES — Britney Spears makes headlines at concerts, even when she’s not performing. That’s probably why Los Angeles radio station KIIS FM tapped the pop princess to guest-host their annual Wango Tango music festival along with Ryan Seacrest on Saturday night at the Staples Center. The bill was a balance of pop and hip-hop, with acts like Ke$ha, Jennifer Lopez, Pitbull, Ne-Yo, Selena Gomez, “Glee” ‘s Matthew Morrison, Lupe Fiasco, T-Pain, Jason Der
