Button: Reference wrapper by its correct name in _destroy()

(cherry picked from commit 7d361e9)

Closes gh-7491
Fixes gh-7490

js/widgets/forms/button.js

@@ -78,8 +78,8 @@ $.widget( "mobile.button", {
 	},
 
 	_destroy: function() {
-			this.element.insertBefore( this.button );
-			this.button.remove();
+			this.element.insertBefore( this.wrapper );
+			this.wrapper.remove();
 	},
 
 	_getIconClasses: function( options ) {

tests/unit/button/button_core.js

@@ -54,4 +54,15 @@
 		deepEqual( button.button( "option", "disabled" ), true, "option disabled is now true" );
 	});
 
+	test( "Destroying a button works correctly", function() {
+		var button = $( "<input type='button' value='Destroy Test'>" ),
+			container = $( "#destroy-test-container" ).append( button ),
+			pristineDOM = container.clone();
+
+		button.button().button( "destroy" );
+
+		deepEqual( $.testHelper.domEqual( container, pristineDOM ), true,
+			"_destroy() leaves DOM unmodified" );
+	});
+
 })( jQuery );

tests/unit/button/index.html

@@ -65,6 +65,7 @@
 			<button id="contains-html">Supports <sup>phrasing content</sup></button>
 			<input type="button" id="val-contains-html" value="<fake markup>"/>
 			<input type="button" id="disabled-state" value="ABC"/>
+			<div id="destroy-test-container"></div>
 		</div>
 	</div>
 </body>