Merge pull request #3082 from stoeckmann/bzip2_dead

The check for end of file (`avail == 0`) happens after the check for a `NULL` return value of `__archive_read_filter_ahead`.

Remove it, because at this stage, it's definitely truncated, not just end of file.

diff --cc libarchive/archive_read_support_filter_bzip2.c
Simple merge