Fix: inadvertent scroll when loading the instructor's extensions tab

[bradenmacdonald]

This minor commit fixes an annoying UI bug with the individual due date extensions, mentioned to me by @sarina in #4868. Whenever an instructor clicked on the "Extensions" tab, the browser would scroll down. This was due to a div having id "view-extensions", conflicting with the tabs script which sets location.hash to "view-[current tab name]" in order to track the current tab.

This was done for OpenCraft ( cc @antoviaque ) and falls under their organization contributor agreement.

[sarina]

@carsongee would you mind taking a look at this small PR when you get a chance?

[sarina]

👍 will merge once tests pass and Carson takes a quick look.

[carsongee]

The view granted extensions portions seems to be broken here. I get a 400 and nothing is displayed. That isn't the case in master

[sarina]

@carsongee do you have a screenshot? Everything worked fine for me...

[carsongee]

In master I get the nice table like so:

but in this branch it just flashes "loading" and disappears and in the test server I get:
[20/Aug/2014 13:00:22] "GET /courses/MITx/8.02r/2014_Spring/instructor/api/show_unit_extensions HTTP/1.1" 400 118

This is clicking the "List all students with due date extensions" button

[carsongee]

and seeing:

Error getting due dates: Missing required query parameter(s) extensions.js:136

in the js console.

[carsongee]

d'oh, wasn't paying close enough attention and missed the coffee file and didn't rebuild assets after switching branches. Sorry about that. 👍

[sarina]

:) thanks for debugging!