vim-patch:7.4.456

Problem:  'backupcopy' is global, cannot write only some
          files in a different way.
Solution: Make 'backupcopy' global-local. (Christian Brabandt)

https://code.google.com/p/vim/source/detail?r=v7-4-456

src/nvim/buffer.c

@@ -1530,6 +1530,7 @@ void free_buf_options(buf_T *buf, int free_p_ff)
   buf->b_p_ar = -1;
   buf->b_p_ul = NO_LOCAL_UNDOLEVEL;
   clear_string_option(&buf->b_p_lw);
+  clear_string_option(&buf->b_p_bkc);
 }
 
 /*