LOS ANGELES (Reuters) - American R&B singer Alicia Keys scored her fifth No. 1 album on the Billboard 200 album chart on Wednesday with "Girl on Fire," unseating reigning chart queen Rihanna. Keys' fifth studio album sold 159,000 copies, according to Nielsen SoundScan, which was the lowest opening week of sales for any of the soulful singer's career. Keys, 31, held off country-pop starlet Taylor Swift's "Red" and Rod Stewart's "Merry Christmas, Baby" for the top spot. ...