By Beth Hardie AlthoughLouis Walsh was left reeling after he was given the boot from the X Factor, behind-the-scenes information about his replacement put a smile back on his face. During the launch show of ITV ’s Celebrity Big Brother, Louis was given the job of being Sharon Osbourne’s advisor and was tasked with helping her decide which three other housemates would be put at risk of being put up for public nomination and potentially evicted from the reality show first. It was something of a role reversal for the pair – who became good friends while working on the X Factor – because Sharon on…