GitLab

- Fixed AutoConnect, which is stored in each network type's subdictionary.
- Added a Cellular.AutoConnect property to ONC.
- Fixed VPN username for L2TP-IPsec, which is stored in 'L2TP'.
- Removed reading Wimax properties from ONC, as these are not yet supported.

BUG=412807

Review URL: https://codereview.chromium.org/571123002

Cr-Commit-Position: refs/heads/master@{#294897}