MB-34324 cbworkloadgen correct estimated messages

Backport progress bar fixes for cbworkloadgen.

Change-Id: Ic914a5606cf99e5eea4978c815ab78af9849e7aa
Reviewed-on: http://review.couchbase.org/109832
Well-Formed: Build Bot <build@couchbase.com>
Reviewed-by: Patrick Varley <patrick@couchbase.com>
Tested-by: Carlos Gonzalez <carlos.gonzalez@couchbase.com>

Author: Carlos Gonzalez Betancort

pump_gen.py

@@ -164,6 +164,12 @@ def total_msgs(opts, source_bucket, source_node, source_map):
         """Returns max-items only if exit-after-creates was specified.
            Else, total msgs is unknown as GenSource does not stop generating."""
         if source_map['cfg']['exit-after-creates'] and source_map['cfg']['ratio-sets'] > 0:
-            total_ops = source_map['cfg']['max-items'] / source_map['cfg']['ratio-sets']
-            return 0, int(total_ops)
+            ratio = source_map['cfg']['ratio-sets']
+            ops = 0
+            sets = 0
+            while sets != source_map['cfg']['max-items']:
+                if ratio >= float(sets)/float(ops or 1):
+                    sets += 1
+                ops += 1
+            return 0, ops
         return 0, None