Revert VirtualBox kernel patch for version 3.17.

No longer needed for VirtualBox 3.16.

This reverts the following commits:

 * 6fc58460ca5d7cce451aaea37ba8051b37c1bc0c
 * 62e2dce98704681cafe67b06e18d3e5ffa037d88

Signed-off-by: aszlig <aszlig@redmoonstudios.org>