(Reuters) - Italian phone group Telecom Italia (TIM) sacked Chief Executive Amos Genish on Tuesday, removing the man who some directors had viewed as an obstacle to their campaign for a more aggressive shake-up at the company.Genish was appointed last year to run the underperforming former monopoly by TIM's then controlling shareholder, French media group Vivendi , but since then directors backed by activist fund Elliott have wrested control of the board. Telecom Italia said in a statement..