Cell width is not updated when a cell is split horizontally

[tmonahan]

To Reproduce:

• Insert a table into CKEditor.
• Apply a width of 200px to the first cell using the Cell Properties dialog.
• Right click in the first cell and select Cell -> Split Cell horizontally. A new cell will be inserted after the selected cell.
• Switch to source view to see the HTML markup for the table.
  

Problem: The cell that was split and the new cell both have a width of 200px. They should each have a width of 100px.

<table border="1" cellpadding="1" cellspacing="1" style="width: 500px;">
	<tbody>
		<tr>
			<td style="width: 200px;">
				&nbsp;</td>
			<td style="width: 200px;">
				&nbsp;</td>
			<td>
				&nbsp;</td>
		</tr>
	             .....
	</tbody>
</table>