ERT-685 INSTALL_JOB_DIRECTORY

The general pattern for these test functions is that they are void, and only return if successfull - i.e. the lines 27 - 30 should be simplified to:

```
test_assert_true( ext_joblist_has_job( joblist , "TROLL_CONTACT"));
```
To achieve this you must include `#include <ert/util/test_util.h>`.