Ternary operator evaluation sometimes fails

After creating global variable var1, the following command fails to parse:
```
echo (false) ? -global.v1 : global.v1
Error:  at column 27: meta command: expected numeric value after '-'
```
If 'false' is replaced by 'true' then the command is processed correctly.

Workaround: replace `-global.v1' by '0-global.v1`.