TWO cut-rate mortgages from failed subprime giant Countrywide Financial continue to cost Sen. Christopher Dodd, shredding the Connecticut Democrat's credibility as he faces re-election next fall. This week, news of the secretive Senate Ethics Committee investigation into Dodd's unusual mortgage deals leaked to The Associated Press. AP reported that at least one witness, Robert Feinberg, starkly contradicted Dodd's account of what favors he knew he was getting from a company that, as a member of the Banking Committee, he helps regulate