Why would Warner have to resign from his seat to run? He would just resign from his seat the day before he was sworn in as governor.
A lot of times politicians in the days after the election and before being sworn in, they resign from their current seat to begin a transitional period to the next.
But why would Warner do that in this case, when doing so means that McDonnell gets to pick the state's next senator? Warner would obviously wait until the last possible minute to resign, so that McDonnell doesn't have time to pick the replacement senator.
