Fix pile-up modules reconfiguration (CMSSW_7_4_X)

[ktf]

The following issues discussed in https://indico.cern.ch/event/344151/session/4/contribution/10/material/slides/0.pdf are addressed:

• clone pile-up modules rather then re-configure them for use after RECO;
• clone isolation modules rather than re-configure them in miniAOD;
• resolve naming circle around top tagger in miniAOD.

Forward port of #6522 to CMSSW_7_4_X. Merging directly since the former is fully approved.

[cmsbuild]

A new Pull Request was created by @ktf (Giulio Eulisse) for CMSSW_7_4_X.

Fix pile-up modules reconfiguration (CMSSW_7_4_X)

It involves the following packages:

CommonTools/ParticleFlow
PhysicsTools/PatAlgos

@nclopezo, @monttj, @cmsbuild, @StoyanStoynev, @slava77, @vadler can you please review it and eventually sign? Thanks.
@rappoccio, @imarches, @ahinzmann, @acaudron, @mmarionncern, @nhanvtran, @schoef, @ferencek, @mariadalfonso, @pvmulder, @TaiSakuma this is something you requested to watch as well.
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