* files.c (is_file_writable): remove assert check for f, since it's not
          initialized at the time.  Fixes Savannah bug 28309, reported by Zoltan Kovacs.



git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@4468 35c25a1d-7b9e-4130-9fde-d3aeb78583b8