title: angular remove form validation after form submit
body: <p>I am working with a small form just have two fields.</p>
  
  <p>1.textarea named message</p>
  
  <p>2.input type file</p>
  
  <p>My form validation is working fine on submit button. But after submitting form selected file does not get blank and validation message for message field does not hide.</p>
  
  <p>My form is below:-</p>
  
  <pre><code>&lt;div ng-controller="discussCtrl"&gt;
    &lt;form name="message_frm" enctype="multipart/form-data" novalidate&gt;
      &lt;div class="control-group" ng-class="{
                                           true : 'error'
                                          } [submitted &amp;&amp; message_frm.message.$valid]"&gt;
        &lt;div class="col-xs-12 text-left"&gt;
          &lt;!--&lt;div class="row"&gt;--&gt;
          &lt;input type="file" ng-file-select="onFileSelect($files)" id="file" name='file' model='discussion.attach' value=""&gt;
          &lt;span class="fileNotice"&gt;Max file size is 1MB, allowed files are .jpeg, .png, .jpg, .gif, .odt, .xls, .doc, .pdf&lt;/span&gt;
          &lt;span ng-show="fileError" id="fileError" class="angular-error simplebox"&gt;Please provide a valid file&lt;/span&gt;
  
        &lt;/div&gt;
        &lt;div class="col-md-12"&gt;
          &lt;div class="boxTextarea"&gt;
            &lt;textarea class="sendMesTextarea" id="frmMessage" name="message" placeholder="Write your message here......" ng-model="discussion.message" ng-minlength="10" ng-maxlength="500" required&gt;&lt;/textarea&gt;
            &lt;span class="angular-error" data-ng-if="message_frm.message.$dirty &amp;&amp; message_frm.message.$invalid"&gt; &lt;/span&gt;
            &lt;span class="angular-error" data-ng-if="(message_frm.message.$dirty || sub) &amp;&amp; message_frm.message.$error.required"&gt;Message required.&lt;/span&gt;
            &lt;span class="angular-error" data-ng-if="(sub &amp;&amp; message_frm.message.$error.minlength) || (message_frm.message.$error.minlength)"&gt;min length is 10 &lt;/span&gt;
            &lt;span class="angular-error" data-ng-if="(sub &amp;&amp; message_frm.message.$error.maxlength) || (message_frm.message.$error.maxlength)"&gt;min length is 500 &lt;/span&gt;
            &lt;div class="buttonsRow"&gt;
              &lt;button type="submit" data-toggle="tooltip" class="greenBtn" ng-click="sub = 1; submitDiscussionData('{{node.id}}')" ng-init="button = 'Send'"&gt;{{button}}&lt;/button&gt;
            &lt;/div&gt;
          &lt;/div&gt;
        &lt;/div&gt;
      &lt;/div&gt;
    &lt;/form&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>and I am using below code in the controller:-</p>
  
  <pre><code>$scope.discussion.messages = '';// This blanks message field
  $scope.discussion.attach = '';////Does not blank file
  $scope.button = 'Send';
  $scope.discussion = '';  //Try to blank model                 
  $scope.message_frm.$setPristine();//Does not works
  $scope.message_frm.$setValidity();//Does not works
  return;
  </code></pre>