Return the first error in group set

If there are couple parameters to set, it will ignore any error that may appear to one of the parameter, except the last one. It marks p_failure_index, but it does not seems to used anywhere.

Scenario for issue: Set group called for two parameters, first one witch is invalid. It will set p_failure_index, but arg->fault will be reset with success since the last parameter is has no failure in "results" field.

So this fix makes return the first dicovered error (arg->fault) if at least one parameter of the group failed to be set.