[Extensions] Update ExtensionManagementTests to manifest v2

ExtensionManagementTests have been updated to manifest v2.
Remove the allowance for manifest v1 extensions.

Bug: 816679
Change-Id: Ib0401a6fdde8e19cdf213769d83dfca73ec98c3d
Reviewed-on: https://chromium-review.googlesource.com/1021660
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552396}
1 file changed