Add some basic argument validation
Add some basic argument validation


Former-commit-id: 0c3b3dfe75d215c09001f9c508530e90605b7cce
TrimBiggs/libcalico,caseydavenport/libcalico,djosborne/libcalico,robbrockbank/libcalico,L-MA/libcalico,plwhite/libcalico,projectcalico/libcalico,tomdee/libnetwork-plugin,tomdee/libcalico,projectcalico/libnetwork-plugin,TrimBiggs/libnetwork-plugin,Symmetric/libcalico,alexhersh/libcalico,insequent/libcalico,TrimBiggs/libnetwork-plugin