By Alan Charlish WARSAW (Reuters) – When Donald Tusk visited the EU headquarters in October to talk about unfreezing funds from the bloc when he likely returns as Poland’s prime minister, it was a meeting of old friends for a man who used to help run the show. “He had lunch at the canteen for regular workers without any protocol, just like a regular guy,” one former official, who declined to be named, said. “It was like a gathering of friends talking about the good old times.” Tusk’s supporters say that bonds formed during his 2014 to 2019 stint as president of the European Council, which grou…