fix the machine poll exiting function (red-hat-data-services#956)

Signed-off-by: Tarun Kumar <[email protected]>

ods_ci/utils/scripts/ocm/ocm.py

@@ -417,7 +417,7 @@ def check_if_machine_pool_exists(self):
             self.cluster_name, self.pool_name
         )
         ret = execute_command(cmd)
-        if ret is None:
+        if not ret:
             return False
         return True