Update vehicle/OVMS.X/vehicle_voltampera.c

change SOC request to 7E4 (7EC) PID 0x8334.
And activate Request to 7E4 during charging cause CAN Bus answers 
request to 7E4 when not active.
 
Merge pull request #104 from mikeljo/patch-4

Update vehicle/OVMS.X/vehicle_voltampera.c