IterateV, IterateKV: provide override for the most common usage pattern
Summary:
The most common usage is to iterate the input container for reading, where you
don't need to use any of these other lambdas.
The least common usage is using all the lambdas except the last one.
So, kill the least commonly used override, adding false explicitly to the call
sites using it. And add an override for the most commonly used pattern,
simplifying all the call sites.
Makes it possible to iterate containers without filling whole terminal screen
with lambdas.
Reviewed By: alexeyt
Differential Revision:
D20130502
fbshipit-source-id:
22a9fcf6585d5d9b5b45d65e7e1845d848b50435