This will make it work regardless of what the current URL happens to be.
Also move the telemetry setting into the options since we might as well
make use of it seeing as how we have to parse it for the base path
anyway.
By design the disable-telemetry flag does not affect extension
telemetry, only the setting does, so disabling the setting when the flag
is set should cause extensions to also stop sending telemetry.
Fixes#1116.
