enableAccount(userName) enables a disabled account. It can
      be invoked with Administrator authority only.
    Parameters
- userName
- A string representing the user name of the user whose account is to be enabled.
Example
The following code snippet toggles the user account status:
    if(people.isAccountEnabled("Joe")){
        people.disableAccount("Joe");        
    }
    else{
        people.enableAccount("Joe");
    }
      
    