Fix T46437: Make progress report py helper resitent to 'zero steps' passed value...

To be backported, should we need an 'a' release.

release/scripts/modules/progress_report.py

@@ -99,7 +99,7 @@ class ProgressReport:
     def enter_substeps(self, nbr, msg=""):
         if msg:
             self.update(msg)
-        self.steps.append(self.steps[-1] / nbr)
+        self.steps.append(self.steps[-1] / max(nbr, 1))
         self.curr_step.append(0)
         self.start_time.append(time.time())