shill: cellular: Support filtering online portals in MobileOperatorInfo.

This CL implements the support for MCCMNC/SID filters in |olp| fields in the
mobile_operator_db databases. These filters are needed to activate vzw for
CDMA/LTE devices separately.

Also added these filters for vzw in additional_providers.prototxt

BUG=chromium:370580
TEST=(1) Run shill_unittest
     (2) Manually test vzw activation flow.

Change-Id: I10c329a7a77ab0972f84ab839ae53bd0bf43749b
Reviewed-on: https://chromium-review.googlesource.com/198597
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>
Commit-Queue: Prathmesh Prabhu <pprabhu@chromium.org>
Tested-by: Prathmesh Prabhu <pprabhu@chromium.org>