config.map: move _THREADED_X to SLC6 and IB/CMSSW_7_1_X/jemalloc341

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
Merge pull request #339 from davidlt/threaded-to-slc6-jemalloc341

config.map: move _THREADED_X to SLC6 and IB/CMSSW_7_1_X/jemalloc341