KABUL (Reuters) - Senior Afghan officials will travel to Pakistan soon to speak to former Taliban No.2 leader Mullah Abdul Ghani Baradar following a breakthrough in negotiations during a London summit, the Afghan presidential palace said on Wednesday. Baradar is a long-time friend of reclusive Taliban leader Mullah Mohammad Omar and is seen by some in Afghanistan as the key to restarting peace talks. British Prime Minister David Cameron is hosting Afghan President Hamid Karzai and Pakistani Prime Minister Nawaz Sharif in London this week for talks on the stalled peace process. ...