Fix module reference to _os
Fix module reference to _os

Change-Id: I0e911c720dd3e5e1e92409c0fd435029f09ef184

dato-code/SFrame,ylow/SFrame,ylow/SFrame,turi-code/SFrame,TobyRoseman/SFrame,ylow/SFrame,ylow/SFrame,TobyRoseman/SFrame,dato-code/SFrame,ylow/SFrame,turi-code/SFrame,dato-code/SFrame,turi-code/SFrame,turi-code/SFrame,turi-code/SFrame,dato-code/SFrame,ylow/SFrame,ylow/SFrame,dato-code/SFrame,TobyRoseman/SFrame,TobyRoseman/SFrame,ylow/SFrame,dato-code/SFrame,turi-code/SFrame,TobyRoseman/SFrame,dato-code/SFrame,TobyRoseman/SFrame,dato-code/SFrame,TobyRoseman/SFrame,turi-code/SFrame,TobyRoseman/SFrame,turi-code/SFrame