Fix case where HC vehicles are remote-spawned with no roads near HQ

[jaj22]

What type of PR is this.

1. Bug
2. Change
3. Enhancement

What have you changed and why?

If high command squads containing vehicles are purchased when the commander is away from HQ, and the HQ has no roads within 100m, the placement code breaks. This PR fixes it to place the vehicle randomly as intended.

Please specify which Issue this PR Resolves.

closes #XXXX

Please verify the following and ensure all checks are completed.

1. Have you loaded the mission in LAN host?
2. Have you loaded the mission on a dedicated server?

Is further testing or are further changes required?

1. No
2. Yes (Please provide further detail below.)

[ante185]

Appears to work as expected.
Vehicles may or may not have an elevated chance of getting damaged or destroyed when spawned in, but it's an substantial improvement over spawning at 0,0,0 and guaranteed to be lost.