Made static sortSegRadius const

The static analyzer was complaining that sortSegRadius was non-const.
Changed this to const and put it in an anonymous namespace.
Reverted MuonDetLayerGeometry using modules back to stream modules

The MuonDetLayerGeometry class was made const thread safe so it
is safe to make the modules which use it stream modules. In addition,
performance tests of the threaded framework were showing some of
these modules were causing bottlenecks when they were legacy modules.
SETMuonSeedProducer uses thread-unsafe CLHEP matricies

SETMuonSeedProducer had to be downgraded to a legacy module since
it uses the thread-unsafe CLHEP matricies in SETFilter::findParabolaMinimum.
Merge pull request #3896 from Dr15Jones/revertMuonDetLayerGeometryUsingModulesToStream

Multithreading -- Revert MuonDetLayerGeometry using modules to stream modules
Merge remote branch 'origin/CMSSW_7_1_X' into CMSSW_7_0_X