Bump lazy-loading waypoint from 110% to 120%

As suggested by Joe in code review here:

  https://gerrit.causes.com/#/c/25810/1/replace.js

We want to be lazy, but not too lazy.

Change-Id: Iaecd53bfc623df0ab939f18cfc067957626b3013
Reviewed-on: https://gerrit.causes.com/25857
Reviewed-by: Joe Lencioni <joe.lencioni@causes.com>
Tested-by: Greg Hurrell <greg@causes.com>