Code cleanups related to RHBZ#580246.

Code cleanups related to RHBZ#580246.

This includes various code cleanups:

 (a) A regression test for RHBZ#580246.

 (b) Use write instead of fwrite to write out the tar file.  This is
     just because the error handling of write seems to be better
     specified and easier to use.

 (c) Use size_t instead of int for length.

 (d) Clearer debug messages when in verbose mode.