virtualbox: 5.1.4 -> 5.1.6

Upstream changelog without bug numbers:

  * GUI: fixed issue with opening '.vbox' files and it's aliases
  * GUI: keyboard grabbing fixes
  * GUI: fix for passing through Ctrl + mouse-click
  * GUI: fixed automatic deletion of extension pack files
  * USB: fixed showing unknown device instead of the manufacturer or
         product description under certain circumstances
  * XHCI: another fix for a hanging guest under certain conditions, this
          time for Windows 7 guests
  * Serial: fixed high CPU usage with certain USB to serial converters
            on Linux hosts
  * Storage: fixed attaching stream optimized VMDK images
  * Storage: reject image variants which are unsupported by the backend
  * Storage: fixed loading saved states created with VirtualBox 5.0.10
             and older when using a SCSI controller
  * Storage: fixed broken NVMe emulation if the host I/O cache setting
             is enabled
  * Storage: fixed using multiple NVMe controllers if ICH9 is used
  * NVMe: fixed a crash during reset which could happen under certain
          circumstances
  * Audio: fixed microphone input (5.1.2 regression)
  * Audio: fixed crashes under certain conditions (5.1.0 regression)
  * Audio: fixed recording with the ALSA backend (5.1 regression)
  * Audio: fixed stream access mode with OSS backend (5.1 regression,
           thanks to Jung-uk Kim)
  * E1000: do also return masked bits when reading the ICR register,
           this fixes booting from iPXE (5.1.2 regression)
  * BIOS: fixed 4bpp scanline calculation
  * API: relax the check for the version attribute in OVF/OVA appliances
  * Windows hosts: fixed crashes when terminating the VM selector or
                   other VBox COM clients
  * Linux Installer: fixed path to the documentation in .rpm packages
                     (5.1.0 regression)
  * Linux Installer: fixed the vboxdrv.sh script to prevent an SELinux
                     complaint
  * Linux hosts: don't use 32-bit legacy capabilities
  * Linux Additions: Linux 4.8 fix for the kernel display driver
  * Linux Additions: don't load the kernel modules provided by the Linux
                     distribution but load the kernel modules from the
                     official Guest Additions package instead
  * Linux Additions: fix dynamic resizing problems in recent Linux
                     guests
  * User Manual: fixed error in the VBoxManage chapter for the
                 getextradata enumerate example

The full upstream changelog with bug numbers can be found at:

https://www.virtualbox.org/wiki/Changelog-5.1#v6



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