title: input file in ipad only let me choose pictures using ionic
body: <p>i'm trying to attach documents to an item using an input file, works well in android i can choose a pdf file, but on the ipad only images can be selected.
  is this a normal behaviour on ipad ?</p>
  
  <pre><code>    &lt;div ng-show="type.mode!=3"&gt;
    &lt;h3&gt;Pièces jointes&lt;/h3&gt;
    &lt;div class="uploader-buttons-container"&gt;
      &lt;!-- PDF uploader --&gt;
      &lt;div class="custom-uploader"&gt;
          &lt;span&gt;Ajouter &lt;strong&gt;PDF&lt;/strong&gt;&lt;/span&gt;
          &lt;input type="file" class="upload" accept="application/pdf" onchange="angular.element(this).scope().pdf(this)" /&gt;
      &lt;/div&gt;
      &lt;!-- Image uploader --&gt;
      &lt;div class="custom-uploader"&gt;
          &lt;span&gt;Ajouter&lt;i class="mini-symbol icon ion-image"&gt;&lt;/i&gt;&lt;/span&gt;
          &lt;input type="file" class="upload" capture="camera" accept="image/*" onchange="angular.element(this).scope().photo(this)" /&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  </code></pre>