title: Laravel 'sometimes' validator fails with nested arrays
body: <p>Am using the Laravel <code>Validator</code> class to do some basic validation on an array.</p>
  
  <p>My array :</p>
  
  <pre><code>$employee['name']='name';
  $employee['address']='address';
  $employee['department']['department_name']='deptname';
  $employee['department']['department_address']='deptaddress';
  </code></pre>
  
  <p>I have the validation rules as below:</p>
  
  <pre><code>$rules = array(
      'name'=&gt; 'required',
      'address' =&gt; 'required',
      'department.department_name' =&gt; 'sometimes|required'
  )
  </code></pre>
  
  <p>And the custom messages as below :</p>
  
  <pre><code>$messages = array(
       'name.required' =&gt; 'Employee Name is required',
       'address.required' =&gt; 'Address is required'
       'department.department_name.required' =&gt; 'Department name is required'
  )
  </code></pre>
  
  <p>I will use <code>Validator::make($employee, $rules, $messages);</code></p>
  
  <p>As per my rules, <code>department_name</code> should be validated if and only if it is present in the array. But currently the <code>Validator</code> is not validating <code>department_name</code> when its present and blank. Any ideas what I might be doing wrong?</p>