Data: do not create data cache when fetching single property

Closes gh-2554

test/unit/data.js

@@ -882,3 +882,19 @@ QUnit.test( "Check that the expando is removed when there's no more data", funct
 		}
 	}
 } );
+
+QUnit.test( ".data(prop) does not create expando", function( assert ) {
+	assert.expect( 1 );
+
+	var key,
+		div = jQuery( "<div/>" );
+
+	div.data("foo");
+	assert.equal( false, jQuery.hasData( div[0] ) );
+	// Make sure no expando has been added
+	for ( key in div[ 0 ] ) {
+		if ( /^jQuery/.test( key ) ) {
+			assert.ok( false, "Expando was created on access" );
+		}
+	}
+} );