Revert chain parameters: zerocoin v2 startheight for main
Revert chain parameters: zerocoin v2 startheight for main

- change zerocoin v2 startheight to block height `1012710`
- First zerocoin v2 created in block `980679`
  TXID: `d74a3dc8722647093b90cd358ba24c6f3b59b5bc6498ec00b888965ea3a38ef1`

ionomy/ion,cevap/ion,cevap/ion,ionomy/ion,ionomy/ion,cevap/ion,cevap/ion,ionomy/ion,ionomy/ion,cevap/ion,cevap/ion,ionomy/ion