solaris_group, pw_group: add missing imports and logger creations

```
************* Module salt.modules.pw_group
E0602: 26,7:add: Undefined variable 'salt'
E0602: 27,8:add: Undefined variable 'log'

************* Module salt.modules.solaris_group
E0602: 27,7:add: Undefined variable 'salt'
E0602: 28,8:add: Undefined variable 'log'
```