Fix import for util function in netns.py
Fix import for util function in netns.py


Former-commit-id: a222e5831c39c55341250783c47a91e598040415
TrimBiggs/libnetwork-plugin,caseydavenport/libcalico,L-MA/libcalico,TrimBiggs/libcalico,djosborne/libcalico,tomdee/libcalico,insequent/libcalico,alexhersh/libcalico,tomdee/libnetwork-plugin,projectcalico/libcalico,Symmetric/libcalico,plwhite/libcalico,robbrockbank/libcalico,projectcalico/libnetwork-plugin,TrimBiggs/libnetwork-plugin