Remove empty help spans from templates.

The empty spans from the templates mess up the layout sometimes, and are useless weight anyway.
Lets get rid of them.

view/theme/frio/templates/field_checkbox.tpl

@@ -4,6 +4,8 @@
 			<input type="checkbox" name="{{$field.0}}" id="id_{{$field.0}}" value="1" {{if $field.2}}checked="checked"{{/if}} aria-checked="{{if $field.2}}true{{else}}false{{/if}}" aria-describedby="{{$field.0}}_tip" {{if $field.4}}{{$field.4}}{{/if}}>
 			<label for="id_{{$field.0}}">
 				{{$field.1}}
+				{{if $field.3}}
 				<span class="help-block" id="{{$field.0}}_tip" role="tooltip">{{$field.3}}</span>
+				{{/if}}
 			</label>
-	</div>
+	</div>