Revert "Merge pull request #687 from dstufft/dont-import-site"
Revert "Merge pull request #687 from dstufft/dont-import-site"

This reverts commit eb88e8f7b20b5d0809013100dc14fe2ebbf738da, reversing
changes made to 6fc1ffa65c7e00e6065522ba3b88ee47e8236dd3.

davidszotten/virtualenv,francatore/virtualenv,vvtam/virtualenv,madprog/virtualenv,RAS-ViVa/virtualenv,techtonik/virtualenv,ionelmc/virtualenv,mykemunson/virtualenv,mykemunson/virtualenv,Lyleo/virtualenv,bigplus/virtualenv,Seha16/virtualenv,dstufft/virtualenv,Seha16/virtualenv,Ivoz/virtualenv,ionelmc/virtualenv,haridsv/virtualenv,bigplus/virtualenv,vvtam/virtualenv,davidszotten/virtualenv,haridsv/virtualenv,kissthink/virtualenv,francatore/virtualenv,RAS-ViVa/virtualenv,Lyleo/virtualenv,techtonik/virtualenv,dstufft/virtualenv,ionelmc/virtualenv,Ivoz/virtualenv,kissthink/virtualenv,madprog/virtualenv