[dashboard][tests] Fix failing unit tests

[Felipe Monteiro]

11 Murano Dashboard unit tests are currently throwing errors (errors=8, failures=3).
For example:
  - http://logs.openstack.org/50/410950/2/check/gate-murano-dashboard-python35-nv/12228d6/console.html

These errors are related to these tests setting 'horizon_pagesize' in the mock request object, then allowing a Horizon function to calculate the pagesize by assuming it looks at the above value. But (probably) Horizon changed this logic, causing errors. The solution is to mock out the function in which the error is originating.

This is the recent Horizon commit that seems to have caused these unit tests
to now fail: https://review.openstack.org/#/c/155939/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/410967

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/410967
Committed: https://git.openstack.org/cgit/openstack/murano-dashboard/commit/?id=11ba34e3c6a4cfff2196025f2659c4d1cf36a13e
Submitter: Jenkins
Branch: master

commit 11ba34e3c6a4cfff2196025f2659c4d1cf36a13e
Author: Felipe Monteiro <email address hidden>
Date: Wed Dec 14 16:40:03 2016 -0500

    Fixes unit tests throwing errors, related to Horizon function.

    Currently, 11 unit tests are failing because Horizon
    changed some of its behavior related to how pagesizes are
    calculated from request objects.

    This is the commit in Horizon that appears to have caused things
    to break in these unit tests:
    https://review.openstack.org/#/c/155939/13/horizon/utils/functions.py

    This fix mocks out the function in Horizon that does the pagesize
    calculation.

    Change-Id: I983e83033b8eab25f79f505d2e57ef1e6b86873b
    Closes-Bug: #1650029

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/murano-dashboard 3.1.0 release.