Be more resilient when querying bugzilla for open bugs

Sometime we fail to retrieve the list of bugs for a component because of
some hick ups with bugzilla.
With this commit, we'll try up to 5 times and wait 20 seconds before
each attempts.
If that still fails, then too bad.

Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>

distgit_bugzilla_sync/script.py

@@ -272,7 +272,22 @@ class BugzillaProxy:
         # Update only maintained releases
         bz_query['version'] = self.config["products"][product]["versions"]
 
-        query_results = self.server.query(bz_query)
+        def _query_bz(query, num_attempts=5):
+            for i in range(num_attempts):
+                try:
+                    raw_data = self.server.query(bz_query)
+                    break
+                except Exception as e:
+                    if i >= num_attempts - 1:
+                        raise
+                    if self.config['verbose']:
+                        print(f"    ERROR {e}")
+                        print("    - Query failed, going to try again in 20 seconds")
+                    # Wait 20 seconds and try again
+                    time.sleep(20)
+            return raw_data
+
+        query_results = _query_bz(bz_query)
 
         for bug in query_results:
             if bug.assigned_to == prev_poc and bug.assigned_to != new_poc: