title: codeigniter form validation set_value works only for the fields which have rules
body: <p>Suppose if I have two fields in my form viz first_name and last_name</p>
  
  <p>I have set the validation rule only for first_name.</p>
  
  <p>set_value should work for both the fields regardless of rule ? right ?</p>
  
  <p>For me it works only for the fields which have rules with them !!! </p>