Fixed crash with "user" Build Variant

"user" Build Variant turns off mock location Secure Setting by
default.
This was causing a crash when svmpd tried to create a mock location
provider.
Added code to enable the setting on boot, before any mock location
providers are created.
Fixes for config changes

Updated WebrtcHandler to support new format for WebRTC message
(ICE servers are now in a JSON array instead of a JSON object).