No network hashrate  ETC parity 2.4.6 MiningCore 4.7
### Description

MiningCore can't load network hashrate with ETC chain 

### Steps to Reproduce

Every time i'm starting  MC app with ethereum-classic config 

 I try with monero and it's works.

### Expected behavior

I would have network hashrate on api reccord.

### Actual behavior

I have 0 Hs on network hashrate data all time

### Reproduces how often

100 %
### Version

MC : 4.7
Parity : 2.4.6

### Additional Information

Linux system ubuntu 16.04 

mining core is very nice, Thanks for that !


