Verge - Groestl block submission error.
### Description

I'm currently testing XVG (Groestl) but daemon rejects found blocks with the error:  `Block 3217487 submission failed with: Block signatures couldn't be created`

I think this issue might be related with this issue: https://github.com/vergecurrency/VERGE/issues/885 

**I'm using v45 btw.**

### Steps to Reproduce

1. Start pool, mine
2. Find block and submit to the daemon.

### Expected behavior

Daemon should accept the block.

### Actual behavior

Daemon rejects the block with the error : `Block XXX submission failed with: Block signatures couldn't be created`

### Reproduces how often

Always

### Version

v45