By Caroline Valetkevitch NEW YORK (Reuters) – The U.S. dollar index was down slightly for a second straight sesson on Wednesday as investors watched for signs on whether tensions in Ukraine could subside, but stronger-than-expected U.S. retail sales data helped to limit the index’s decline. The index briefly pared losses after data showing U.S. retail sales rebounded sharply in January, which bolstered the case for interest rate hikes from the U.S. Federal Reserve starting in March. Expectations that the Fed will raise rates have helped to give support to the dollar. Investors also are awaitin…