By John Revill and Shubham Kalia ZURICH (Reuters) - Nestle Chairman Paul Bulcke will step down early and hand over to former Inditex chief Pablo Isla on October 1, accelerating a changing of the guard at the Swiss food giant after an unprecedented period of managerial turmoil. The decision comes just weeks after Laurent Freixe was abruptly fired as chief executive over an undisclosed relationship, and clears the way for new CEO Philipp Navratil and Isla to take full charge of the company that has struggl ...