I don't think that the v you describe is part of RFC6979RFC6979 because I cannot find it in that document. This v happens to be part of the ecdsa_raw_sign
raw sign function in pybitcointools, which calls deterministic_generate_k
, which is an implementation of RFC6979.
RFC6979 just helps you generate a deterministic k value for signing. It does not help you generate r and s. To generate r and s, you just use the normal ECDSA algorithm; you don't have to refer to RFC6979 after you have used it to generate k. RFC6979 generates k, which is an input to the signing algorithm that can generate r and s.