gpgtar: Fix extracting files with !(size % 512)
* tools/gpgtar-extract.c (extract_regular): Handle size multiples of RECORDSIZE.
If a hdr->size was a multiple of 512 the last record would not have been written and the files corrupted accordingly.
Changed to use only if-else.
- GnuPG-bug-id: T1926
- Signed-off-by: Werner Koch <wk@gnupg.org>