Reduce Linux box size by not packing a swap partition

* Whiteout swap partition for CentOS, Debian, Fedora, OpenSUSE, Oracle,
  RHEL, SLES, Ubuntu
* FreeBSD has no support for blkid, left it as is
Merge pull request #281 from ceetav/noswap

Reduce Linux box size by not packing a swap partition gubbish