Use the horizon_pagesize value in the session cookie

This makes the API calls that are claiming to do pagination work
the same as Nova, which has had it the longest.  Namely, there's a
user setting to control how many rows get returned.  Make them heed
it.

Fixes Bug: 1217608
Change-Id: I19b4d7c77d595b898abb81462f6343bbc1b93eb6
Merge "Use the horizon_pagesize value in the session cookie"