[Bug c++/58140] -Wnon-virtual-dtor shouldn't fire for classes declared final

[tudorb at fb dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58140

--- Comment #1 from Tudor Bosman <tudorb at fb dot com> ---
(Tested with gcc 4.7.1, compiled with -std=c++11 -Wnon-virtual-dtor