Change return type of getter in ExtJob

We like to avoid passing the C type containers out into the
python interface, and rather create ordinary python list.

python/res/job_queue/ext_job.py

@@ -201,10 +201,12 @@ def get_license_path(self):
         return self._get_license_path()
 
     def get_arglist(self):
-        return self._get_arglist()
+        # The return type is cast from a <StringList> to a regular Python list.
+        return list(self._get_arglist())
 
     def get_argvalues(self):
-        return self._get_argvalues()
+        # The return type is cast from a <StringList> to a regular Python list.
+        return list(self._get_argvalues())
 
     def set_arglist(self, args):
         return self._set_arglist(args)