Remove an unused member in RenderTable::ColumnStruct

Remove an unused member in RenderTable::ColumnStruct
https://bugs.webkit.org/show_bug.cgi?id=69119

Reviewed by Darin Adler.

No test as there should be no change in behavior.

The member was added several years ago and its users were removed or changed. The code would
need a refactoring but this would be tricky to get right. This change just removes the member
to reap the short-term benefits.

* rendering/RenderTable.h:
(WebCore::RenderTable::ColumnStruct::ColumnStruct): Remove anything associated with m_width.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@96476 268f45cc-cd09-0410-ab3c-d52691b4dbfc