List alternative versions of halo catalogs when there is no match

Suppose the user knows that there is a `bolshoi` catalog at z ~ 0.35 stored in cache, but cannot remember the `version_name`:

```
>>> halocat = CachedHaloCatalog(simname='bolshoi', redshift=0.35)
```

In the current code, if there is no match, there will be an error message printing out the list of available catalogs with `default_version_name`, but none with the alternate version name, even if the redshift is an exact match to the alternate version name.