Header images: Handle cropping failures.

props ehg.
see #21785.


git-svn-id: https://develop.svn.wordpress.org/trunk@27946 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/media-template.php

@@ -1048,6 +1048,11 @@ function wp_print_media_templates() {
 		<div class="wpview-overlay"></div>
 	</script>
 
+	<script type="text/html" id="tmpl-crop-content">
+		<img class="crop-image" src="{{ data.url }}">
+		<div class="upload-errors"></div>
+	</script>
+
 	<?php
 
 	/**