Deletes blob references for the given signed binary from the DB.

def DeleteSignedBinaryReferences(self,
                                   binary_id,
                                   cursor=None):
    """Deletes blob references for the given signed binary from the DB."""
    cursor.execute(
        """
      DELETE FROM signed_binary_references
      WHERE binary_type = %s AND binary_path_hash = %s
    """, [
        binary_id.binary_type.SerializeToDataStore(),
        mysql_utils.Hash(binary_id.path)
    ])