David J. Rush, the former C.I.A. officer found last month with $40 million in gold bars in his home and now under F.B.I. investigation, had powerful friends in government. It turns out that one of them, Stephen A. Feinberg, the deputy secretary of defense, even contacted the C.I.A. earlier this year asking to work more closely with him. Before the C.I.A. fired Mr. Rush, he and Mr. Feinberg worked together on a highly classified program focused on spying on China, according to the current and former officials. Mr. Feinberg reached…