WASHINGTON, Oct 3 (Reuters) - An FBI agent was relieved of duty for declining to arrange a "perp walk" of the bureau's former director, James Comey, in front of news media cameras after Comey was federally charged last month, four people briefed on the matter said on Friday.Comey was charged on September 25 with making false statements and obstructing a congressional investigation, in a dramatic escalation of President Donald Trump's retribution campaign against his political enemies.An FBI spokeswoman declined to comment on personnel matters.Reuters could not immediately determine how or when senior FBI officials wanted to stage bringing Comey into...