shill: cellular: Migrate network_SIMLocking to new test_environment

BUG=chromium:415293
TEST=network_SIMLocking

Change-Id: I910e598c528687bed40311a090b1a156db2c8d0a
Reviewed-on: https://chromium-review.googlesource.com/227163
Reviewed-by: Thieu Le <thieule@chromium.org>
Commit-Queue: Roshan Pius <rpius@chromium.org>
Tested-by: Roshan Pius <rpius@chromium.org>
1 file changed