CRM-16243 - Redundant installation should not throw error

CRM-16243 - Redundant installation should not throw error

Suppose we have two modules, `foo.core` and `foo.addon` (where `foo.addon`
depends on `foo.core`).

Now you suppose you try to install `foo.addon` twice, e.g.

```
cv en foo.addon
cv en foo.addon
```

The first installation succeeds (and enables both modules as expected).
However, the second installation throws an error: "Dependency foo.core not
found, required by foo.addon"

This adds a test and resolves the error.