Description of problem:
Configuration -> Tasks page contains a list of various tasks executed / to be
executed by the application. The list always contains navigation buttons: first,
previous, next, last.

Normally, the navigation works OK and navigating through the list
would mean doing requests like:

    GET /miq_proxy/change_tab?page=2&tab=2
    GET /miq_proxy/change_tab?page=3&tab=2
    GET /miq_proxy/change_tab?page=4&tab=2

Though after pressing the "Reload" button, which is the following request:

    POST /miq_proxy/button?pressed=miq_task_reload

the received tasks list is rendered incorrectly and navigating
through the list would try to do the following request:

    GET /miq_proxy/button?page=2&pressed=miq_task_reload

which generates an ISE:

Started GET "/miq_proxy/button?page=2&pressed=miq_task_reload"
ActionController::RoutingError (No route matches [GET] "/miq_proxy/button"):

In another words, pressing the reload button results into
an incorrectly rendered tasks list.


Version-Release number of selected component (if applicable):
CFME 5.3

How reproducible:
Always

Steps to Reproduce:
1. Navigate to Configuration -> Tasks page
2. Navigate through the rendered tasks list (next, previous, etc.)
3. Hit reload & try to navigate throught the list again

Actual results:
Internal server error

Expected results:
The navigation works correctly.

Additional info:
https://github.com/ManageIQ/manageiq/issues/1182