negcache_files: got rid of large array on stack
Removed large buffer from function stack.
It is safe to use single (static) global buffer since:
1) Responders are single threaded
2) Code doesn't use content of this buffer anyway
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
(cherry picked from commit 8e6656c974ac05bb52607014bb4c30b87f4abd8b)
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>