Use dynamic loader from CMSSW to load CMSSW

This uses dynamic loader from CMSDIST glibc package. Package includes
TLS/thread-safety patches.

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
Merge pull request #4265 from davidlt/cmsrun-glibc-tls-threaded

Use dynamic loader from CMSSW to load cmsRun