Update rubygem-kafo to 0.0.15-1.el6

- Fixes #3084 - PTY.check should never return nil (mhulan@redhat.com)
Update rubygem-kafo to 0.0.15-1.fc18

- Fixes #3084 - PTY.check should never return nil (mhulan@redhat.com)
Update rubygem-kafo to 0.0.15-1.fc19

- Fixes #3084 - PTY.check should never return nil (mhulan@redhat.com)