Allow environment variable to set local IP used in STs
Allow environment variable to set local IP used in STs


Former-commit-id: b9a0242f763fc4edcbf3c48279b1d408bc3ed83d
plwhite/libcalico,djosborne/libcalico,tomdee/libnetwork-plugin,Symmetric/libcalico,alexhersh/libcalico,robbrockbank/libcalico,projectcalico/libcalico,caseydavenport/libcalico,TrimBiggs/libnetwork-plugin,TrimBiggs/libnetwork-plugin,tomdee/libcalico,projectcalico/libnetwork-plugin,insequent/libcalico,TrimBiggs/libcalico,L-MA/libcalico