securid: Move common v2/v3 logic into securid_encode_token()
securid: Move common v2/v3 logic into securid_encode_token()

Signed-off-by: Kevin Cernekee <3105dbb3dd63fbb4f6371cfb04adc6726f76c56b@gmail.com>

cernekee/stoken,mtmiller/stoken,mtmiller/stoken,cernekee/stoken,mtmiller/stoken,cernekee/stoken,mtmiller/stoken,cernekee/stoken