[Extensions] Update app shim handler test to use manifest v2

Update extension_app_shim_handler_mac_unittest.cc to generate
extensions with manifest_version 2.

Bug: 816679
Change-Id: If39956a5b8b986da6d84957e91849cfe670346a0
Reviewed-on: https://chromium-review.googlesource.com/1008175
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549974}
1 file changed