--tar option broken

drush_make_tar() is busted.

here's the line in question: drush_shell_exec("tar -C%s -s/__build__/%s/ -Pc __build__ | gzip > %s", $tmp_path, basename($base_path, '.tar.gz'), $base_path);

the big problem is that it looks like the -s switch is being used like a regex, but in reality the -s switch for tar does this: "list of names to extract is sorted to match archive".

also, the output is being piped through gzip manually, which isn't necessary -- the -z switch can take care of that.

attached patch fixes the problem in local testing. i didn't see any other switch for tar that would let you substitute the name of the directory prior to tar'ing, so i just do an ol' fashioned mv -- the entire temp dir is wiped clean anyways before the end of the cycle, so this works fine and doesn't leave any mess.