miner: indentation fixes, remove for (;;)
miner: indentation fixes, remove for (;;)

- change a for (;;) into while (true), as we nowhere else use the first
- init nNonceFound to 0
- fix indentation in BitcoinMiner try/catch block

(cherry picked from commit 0655fac0b11c7fa1992f50537887728a0878a5eb)

reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin