Revert "ensure that virtualenv is installed before making virtualenv"
Revert "ensure that virtualenv is installed before making virtualenv"

This reverts commit 0f55be6e8133d038129607d0982ecdcbfddfcc96.

phac-nml/irida-galaxy-importer,phac-nml/irida-galaxy-importer,phac-nml/irida-galaxy-importer