isDateStart modify

<!--    <b:if cond='data:post.isDateStart'> -->
          <b:if cond='data:post.isFirstPost == &quot;false&quot;'>
            &lt;/div&gt;&lt;/div&gt;
          </b:if>
<!--    </b:if> -->
<!--    <b:if cond='data:post.isDateStart'> -->
          &lt;div class=&quot;date-outer&quot;&gt;
<!--    </b:if> -->
        <b:if cond='data:post.dateHeader'>
          <h2 class='date-header'><span><data:post.dateHeader/></span></h2>
        </b:if>
<!--    <b:if cond='data:post.isDateStart'> -->
          &lt;div class=&quot;date-posts&quot;&gt;
<!--    </b:if> -->