make fakes3 detection more reliable and python <2.6 compatible
make fakes3 detection more reliable and python <2.6 compatible

carolFrohlich/nipype,mick-d/nipype,carolFrohlich/nipype,mick-d/nipype,mick-d/nipype,carolFrohlich/nipype,carolFrohlich/nipype,mick-d/nipype