rename_inames does not map domains

For eg:
```python
knl = lp.make_kernel(
[
"{ [i]: 0<=i<10 }",
"{ [k]: 0<=k= 0 }
```

Looking at the intermediate domains before unused inames are removed we see the issue.
```
{ [i, j] : 0 <= i <= 9 and 0 <= j <= 9 }
[i] -> { [k] : 0 <= k < i }
```
Note that the domain with `k` does not have `j` in it.