Bug 1304148 - Simplify the code in the job-log-url endpoint

Reduce the number of SQL queries from 3 to just 1

treeherder/webapp/api/job_log_url.py

@@ -31,8 +31,6 @@ class JobLogUrlViewSet(viewsets.ReadOnlyModelViewSet):
         GET method implementation for list view
         job_id -- Mandatory filter indicating which job these log belongs to.
         """
-        repository = Repository.objects.get(name=project)
-
         job_id = request.query_params.get('job_id')
         if not job_id:
             raise ParseError(
@@ -42,7 +40,7 @@ class JobLogUrlViewSet(viewsets.ReadOnlyModelViewSet):
         except ValueError:
             raise ParseError(detail="The job_id parameter must be an integer")
 
-        jobs = Job.objects.filter(repository=repository,
-                                  project_specific_id=job_id)
-        return Response([self._log_as_dict(log) for log in
-                         JobLog.objects.filter(job__in=jobs)])
+        logs = JobLog.objects.filter(job__repository__name=project,
+                                     job__project_specific_id=job_id)
+
+        return Response([self._log_as_dict(log) for log in logs])