Refactors VIF configuration logic

There are too many if/else checks when we choose the right function to
conduct vif operations. We can do better by getattr on the nessesary
function obj. The vif type needs normalization to remove periods.

Change-Id: I6bb2af45d3e72bdc11470877fd2a993e9d0a4623
Merge "Refactors VIF configuration logic"