and use dedicated knobs for every option used in
former SimpleConnectProperties.
New section is [MobileNetwork] with the following configuration options:
APN=
AllowedAuthenticationMechanisms==
User=
Password=
IPFamily=
AllowRoaming=
PIN=
OperatorId=
When removing marked routes, the condition `if (ret)` incorrectly
overwrites any previously accumulated error in `ret` with the latest
return value `r`, even if `r >= 0` (success). This means an earlier
real error can be silently cleared by a subsequent successful
route_remove() call.
The parallel address_remove() block just above uses the correct
`if (r < 0)` pattern. Apply the same fix to the route_remove() block.