gitlab: simplify CIJobs a bit

Rather than special-casing the first page, start out with an empty
list and append each page. This is slightly less effective, but
will make it easier to modify the list before returning it.

internal/gitlab/gitlab.go

@@ -839,14 +839,7 @@ func CIJobs(pid interface{}, sha string) ([]*gitlab.Job, error) {
 			PerPage: 500,
 		},
 	}
-	list, resp, err := lab.Jobs.ListPipelineJobs(pid, target, opts)
-	if err != nil {
-		return nil, err
-	}
-	if resp.CurrentPage == resp.TotalPages {
-		return list, nil
-	}
-	opts.Page = resp.NextPage
+	list := make([]*gitlab.Job, 0)
 	for {
 		jobs, resp, err := lab.Jobs.ListPipelineJobs(pid, target, opts)
 		if err != nil {