Fix lua error mount/unmount vehicle

[Neogeekmo]

Fix for this lua error:

141x ...ceShadowedUnitFrames/modules/combopoints.lua:27: Usage: local result = GetComboPoints(unit, target)
[string "=[C]"]: in function `GetComboPoints'
[string "@ShadowedUnitFrames/modules/combopoints.lua"]:27: in function `GetPoints'
[string "@ShadowedUnitFrames/modules/basecombopoints.lua"]:180: in function `Update'
[string "@ShadowedUnitFrames/modules/combopoints.lua"]:40: in function `?'
[string "@ShadowedUnitFrames/modules/units.lua"]:36: in function `FullUpdate'
[string "@ShadowedUnitFrames/modules/units.lua"]:1556: in function <ShadowedUnitFrames/modules/units.lua:1520>

Locals:
(*temporary) = "vehicle"