network: use 'command -v ip' to test for the ip executable
network: use 'command -v ip' to test for the ip executable

This is an improved test because it doesn't require the ip executable to be
in a specific path.

OpenRC/openrc,williamh/openrc,williamh/openrc,williamh/openrc,dwfreed/openrc,OpenRC/openrc,dwfreed/openrc,dwfreed/openrc,OpenRC/openrc