Remove custom dynamic loader from any SLC version, expect SLC6

[davidlt]

The following bugs has been backported to RHEL 7.2 on our request:

• BZ HLT development incl. use of v4 of L1T (80X) #13862 // Reuse of cached stack can cause bounds overrun of thread
  DTV
• BZ Create Bs_phiphi_4K.dec #17090 // Assertion failure (map->l_tls_modid == cnt) when
  dlopen()ing initial-exec TLS shared objects under certain circumstances
• BZ Package of several technical changes: downgrade of edm::Warnings to edm::Info, removal of an unused parameter from cfi file, upward move of jet selection for tau seeding, switch off of production of null taus #17620 // DTV_SURPLUS limits loading of Static TLS-requiring modules
  in multi-threaded programs
• BZ Updated neutron background simulation #17621 // DTV update for Static TLS dlopened modules is racy
• BZ pr90 simHCALTPDigis Back in phase2_hcal Sequence. #17628 // nptl_db's td_thr_tls* don't check DTV generation

There is no need to continue shipping a custom version of dynamic loader
for CentOS 7.2.1511 or above.

All the fixes are within glibc-rh1189278.patch and glibc-rh1202952.patch
on glibc source RPM.

Will resolve cmsRun segfaults on CentOS 7.2.1511.

Signed-off-by: David Abdurachmanov David.Abdurachmanov@cern.ch

[cmsbuild]

A new Pull Request was created by @davidlt for CMSSW_8_0_X.

It involves the following packages:

FWCore/Framework
FWCore/ParameterSet
FWCore/PluginManager
HLTrigger/Tools

@perrotta, @smuzaffar, @cmsbuild, @Martin-Grunewald, @Dr15Jones, @fwyzard, @davidlange6 can you please review it and eventually sign? Thanks.
@Martin-Grunewald, @wddgit, @wmtan this is something you requested to watch as well.
@slava77, @Degano, @smuzaffar you are the release manager for this.

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