puppi bug fix 73x from JOtt

[nhanvtran]

PUPPI bug fix for 73x too.

Is this okay?

[cmsbuild]

A new Pull Request was created by @nhanvtran for CMSSW_7_3_X.

puppi bug fix 73x from JOtt

It involves the following packages:

CommonTools/PileupAlgos

@nclopezo, @cvuosalo, @monttj, @cmsbuild, @slava77, @vadler can you please review it and eventually sign? Thanks.
@ahinzmann, @rappoccio this is something you requested to watch as well.
You can sign-off by replying to this message having '+1' in the first line of your reply.
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@nclopezo you are the release manager for this.
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[cvuosalo]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

+1
Tested at: 2ef660b
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-7735/2598/summary.html

[cvuosalo]

+1

For #7735 2ef660b

Identical to #7733, except intended for 7_3_X rather than 7_4_X, this PR makes small code changes to protect against a possible division by zero and a possible negative array index reference. Prior to this fix, programs that encountered these special situations would probably have crashed.

Jenkins tests show no problems or differences, but this PR would not be expected to cause any change in program behavior except in the very rare cases where the particular situations it protects against occur.

[slava77]

is bot asleep? there was a +1 from reco

[slava77]

+1

trying to convince cms-bot
#7735 (comment)