spigots: Add ability to mark networks/certs for removal

Also changes to use "remove" vs "delete" terminology
consistently with onc spec.  Removes unnecessary indenting.

BUG=chromium-os:19701
TEST=remove on unpublished certs/networks,
     remove on published certs/networks,
     load/save mixed removed network/certs

Change-Id: I769bb06e45263f8606a1e4728b901e50332f7b79
3 files changed