Fix return-type and value of Pathing::GetApproximateLength

Changes generation of this not very useful code (ORIGINAL):
```
EXPORT(float) bridged_Pathing_getApproximateLength(int skirmishAIId, float* start_posF3, float* end_posF3, int pathType, float goalRadius) {

	struct SGetApproximateLengthPathCommand commandData;
	int internal_ret;
	commandData.start_posF3 = start_posF3;
	commandData.end_posF3 = end_posF3;
	commandData.pathType = pathType;
	commandData.goalRadius = goalRadius;

	internal_ret = id_clb[skirmishAIId]->Engine_handleCommand(skirmishAIId, COMMAND_TO_ID_ENGINE, -1, COMMAND_PATH_GET_APPROXIMATE_LENGTH, &commandData);

	internal_ret = commandData.ret_approximatePathLength;
	if (internal_ret == 0) {
		internal_ret = commandData.ret_approximatePathLength;
	} else {
		internal_ret = 0;
	}
	return internal_ret;
}
```
to more meaningful code (FIXED):
```
EXPORT(float) bridged_Pathing_getApproximateLength(int skirmishAIId, float* start_posF3, float* end_posF3, int pathType, float goalRadius) {

	struct SGetApproximateLengthPathCommand commandData;
	int internal_ret;
	commandData.start_posF3 = start_posF3;
	commandData.end_posF3 = end_posF3;
	commandData.pathType = pathType;
	commandData.goalRadius = goalRadius;

	internal_ret = id_clb[skirmishAIId]->Engine_handleCommand(skirmishAIId, COMMAND_TO_ID_ENGINE, -1, COMMAND_PATH_GET_APPROXIMATE_LENGTH, &commandData);

	if (internal_ret == 0) {
		return commandData.ret_approximatePathLength;
	} else {
		return (float)0;
	}
}
```
That way function will return proper value instead of always 0.

PS: Strange behavior noticed. If start point = end point then length is always 10. Not a big problem and its anyway ApproximateLength.