This reverts commit 8402be3b.

Ran these suckers through ImageOptim, which crunched 'em down real nice.

 cms/static/images/bg-micro-stripes.png              | Bin 117 -> 102 bytes
 cms/static/images/choice-example.png                | Bin 2751 -> 1544 bytes
 cms/static/images/drag-handles.png                  | Bin 954 -> 103 bytes
 cms/static/images/explanation-example.png           | Bin 4772 -> 4671 bytes
 cms/static/images/header-example.png                | Bin 6639 -> 385 bytes
 cms/static/images/hiw-feature1.png                  | Bin 67031 -> 66798 bytes
 cms/static/images/hiw-feature2.png                  | Bin 17027 -> 16408 bytes
 cms/static/images/hiw-feature3.png                  | Bin 15092 -> 14775 bytes
 cms/static/images/large-video-icon.png              | Bin 234 -> 128 bytes
 cms/static/images/multi-example.png                 | Bin 2875 -> 1519 bytes
 cms/static/images/number-example.png                | Bin 1430 -> 515 bytes
 cms/static/images/preview-lms-staticpages.png       | Bin 61450 -> 53417 bytes
 cms/static/images/problem-editor-icons.png          | Bin 2307 -> 2304 bytes
 cms/static/images/search-icon.png                   | Bin 1196 -> 423 bytes
 cms/static/images/select-example.png                | Bin 1961 -> 1006 bytes
 cms/static/images/string-example.png                | Bin 1458 -> 574 bytes
 cms/static/images/studio-logo.png                   | Bin 4243 -> 885 bytes
 cms/static/images/thumb-hiw-feature1.png            | Bin 16516 -> 16311 bytes
 cms/static/images/thumb-hiw-feature2.png            | Bin 12956 -> 12821 bytes
 cms/static/images/thumb-hiw-feature3.png            | Bin 16616 -> 16395 bytes
 common/static/css/vendor/ova/video-js.fw.png        | Bin 78899 -> 74914 bytes
 .../css/vendor/pdfjs/images/loading-small.png       | Bin 7402 -> 613 bytes
 .../css/vendor/pdfjs/images/loading-small@2x.png    | Bin 16131 -> 1324 bytes
 .../secondaryToolbarButton-documentProperties.png   | Bin 403 -> 402 bytes
 .../css/vendor/slickgrid/images/drag-handle.png     | Bin 1130 -> 94 bytes
 25 files changed, 0 insertions(+), 0 deletions(-)

OPEN-307

We need to use an Open edX footer by default (and that's what all non-edx.org
instances should base their footer off) and only use the edX footer on
edx.org.

This commit uses `SITE_NAME` to determine which footer to use.

Sites using theming or micro-sites with a `SITE_NAME` not ending in `edx.org`
should not be affected.