Some errors during namespace reloading are lost

In some cases the original error is not thrown and instead error about namespace not being found is thrown.

```
                    java.lang.Exception: namespace 'backend.x.sync' not found
clojure.lang.Compiler$CompilerException: java.lang.Exception: namespace 'backend.x.sync' not found, compiling:(backend/admin/api.clj:1:1)
```