labs: rename local vars: functions
labs: rename local vars: functions

Make local variables lowercase and some of them more descriptive.

Change-Id: I975543194d58399a83fe2d78a26694c7e881c19f

harrisonfeng/training-guides,openstack/training-guides,Nabs007/training-guides,Nabs007/training-guides,harrisonfeng/training-guides,Nabs007/training-guides,openstack/training-guides,harrisonfeng/training-guides