distro: remove default connectivity check urls
distro: remove default connectivity check urls

The connectivity checks were a copy and paste from a reference distro
when overc was initially created. They haven't been kept up to date,
so it is best to let them be empty and defined by someone doing a build
(so they can't point to a reliable source they have vetted)

Signed-off-by: Bruce Ashfield <284cc737d174a260eec2a2a6324a304f84b1ae0f@gmail.com>

OverC/meta-overc,OverC/meta-overc,OverC/meta-overc,OverC/meta-overc,OverC/meta-overc,OverC/meta-overc