By Christian Kraemer and Miranda Murray BERLIN (Reuters) -German Economy Minister Robert Habeck expressed concern about violent protests on Friday after a crowd of demonstrating farmers blocked him from disembarking from a ferry and tried to storm the vessel in a row over subsidy cuts. “What worries me is that the mood in this country is heating up so much,” said Habeck in a statement. “As a minister, I have the protection of the police. Many, many others have to fend off attacks on their own and cannot share their uncertainty,” he added. Video of the blockade on social media showed dozens of …