[Extensions] Update background application list model test to use manifest v2

Update background_application_list_model_unittest.cc to generate
extensions with manifest_version 2.

Bug: 816679
Change-Id: Icb245afea008fb2bdf57ae20e7289539aa39724e
Reviewed-on: https://chromium-review.googlesource.com/1008605
Commit-Queue: Drew Wilson <atwilson@chromium.org>
Reviewed-by: Drew Wilson <atwilson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550142}
1 file changed