update set_value for name and slug

Updated set_value('name', $name) and set_value('slug', $slug) 
to set_value('name', $sample->name) and set_value('slug', $sample->slug).

Otherwise the variables give a PHP error.

views/admin/form.php

@@ -12,12 +12,12 @@
 		<ul>
 			<li class="<?php echo alternator('', 'even'); ?>">
 				<label for="name"><?php echo lang('sample:name'); ?> <span>*</span></label>
-				<div class="input"><?php echo form_input('name', set_value('name', $name), 'class="width-15"'); ?></div>
+				<div class="input"><?php echo form_input('name', set_value('name', $sample->name), 'class="width-15"'); ?></div>
 			</li>
 
 			<li class="<?php echo alternator('', 'even'); ?>">
 				<label for="slug"><?php echo lang('sample:slug'); ?> <span>*</span></label>
-				<div class="input"><?php echo form_input('slug', set_value('slug', $slug), 'class="width-15"'); ?></div>
+				<div class="input"><?php echo form_input('slug', set_value('slug', $sample->slug), 'class="width-15"'); ?></div>
 			</li>
 		</ul>
 
@@ -29,4 +29,4 @@
 
 	<?php echo form_close(); ?>
 
-</section>
+</section>