Remove PKCS5_pbe2_set_iv()

Remove PKCS5_pbe2_set_iv()

This used to be a generalization of PKCS5_pbe2_set(). Its only caller was
the latter, which always passes aiv == NULL and pbe_prf == -1. Thus, the
iv would always be random and regarding the pbe_prf, it would always end
up being NID_hmacWithSHA1 since the only ctrl grokking EVP_CTRL_PBE_PRF_NID
was RC2's control, but only if PBE_PRF_TEST was defined, which it wasn't.

ok jsing