PARKLAND, Fla. (Reuters) - The Federal Bureau of Investigation said on Friday it had failed to act on a tip warning that the man now accused of killing 17 people at a Florida high school possessed a gun, the desire to kill and the potential to commit a school shooting. The disclosure sparked angry disbelief from residents of the Miami suburb of Parkland still reeling from Wednesday’s massacre, the deadliest shooting ever at a U.S. high school, and led Florida’s governor to call for the FBI chief to resign.