JCLOUDS-457: JobStatus has been added

Now the job status is stored as an enum instead of
a String. This is useful when comparing the status to
check if a job is completed, failed or still in progress.
Sorry I see what you are doing here.  Instead you can build up the `Map` via:

```
private static final Map<String, JobStatus> STRING_TO_ENUM;
static {
    ImmutableMap.Builder<String, JobStatus> builder = ImmutableMap.builder();
    for (JobStatus status : values()) {
        builder.add(CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.UPPER_CAMEL, status.toString(), status);
    }
    STRING_TO_ENUM = builder.build();
}
```