Remove unused Chromevox classic background script.

Remove unused Chromevox classic background script.

Chromevox classic and next background scripts have been compiled
togetehr
for a long while, so no need to ship that script anymore.

BUG=None

Committed: https://crrev.com/8100ba3b1009de1d5a8f9b7c3ad8e9b36cc3c407
Cr-Commit-Position: refs/heads/master@{#351075}

[Peter Lundblad, 2015-09-28 14:49:00]

plundblad@chromium.org changed reviewers:
+ dmazzoni@chromium.org

[dmazzoni, 2015-09-28 15:30:01]

The CQ bit was checked by dmazzoni@chromium.org

[dmazzoni, 2015-09-28 15:30:01]

lgtm

[commit-bot: I haz the power, 2015-09-28 15:30:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1371913004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1371913004/1

[commit-bot: I haz the power, 2015-09-28 16:04:36]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-28 16:05:29]

Patchset 1 (id:??) landed as
https://crrev.com/8100ba3b1009de1d5a8f9b7c3ad8e9b36cc3c407
Cr-Commit-Position: refs/heads/master@{#351075}