Improve cleanup to run once a day (except for deleting empty runs)

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Most cleanup now only happens one time a day (in first run of the day).
Cleanup used to run in every run; this is mostly not useful as cleanup limits 
in bots.ini are based on days.
Only cleanup done for every run is the removal of new runs without received 
files; this can be indicated in bots.ini per hours.

While doing this I improve the algorithm for deleting the removals of new runs 
without received files:
- if nothing received (and no process errors) the ta's of such are run are 
deleted in automatic maintenance.
- set 'ts' as index of table 'report'
- delete such runs in table 'report' only for last 25 hours because the 
cleaning up would runs over whole report table each time.

Original issue reported on code.google.com by hjebb...@gmail.com on 31 Aug 2012 at 1:25

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Original comment by hjebb...@gmail.com on 31 Mar 2013 at 11:49

• Changed state: Fixed

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Original comment by hjebb...@gmail.com on 10 Sep 2013 at 12:45

• Changed state: Done