BERLIN/FRANKFURT (Reuters) – Ferdinand Piech, who resigned as chairman of Volkswagen over the weekend, sowed the seeds of his own demise by reneging on a deal to support CEO Martin Winterkorn and secretly plotting to oust him instead, according to sources close to the VW board. When news leaked out last week that Piech had been lobbying family members behind the scenes to install Matthias Mueller, the chief executive of Porsche, at the helm of VW, the company’s powerful works council and its home state of Lower Saxony – a top shareholder – decided they had had enough.