libxl: initialize vfb defbools in libxlMakeVfb
libxl: initialize vfb defbools in libxlMakeVfb

If the domU configu has sdl enabled libvirtd crashes:
libvirtd[5158]: libvirtd: libxl.c:343: libxl_defbool_val:
Assertion `!libxl_defbool_is_default(db)' failed.

Initialize the relevant defbool variables in libxl_device_vfb.

Signed-off-by: Olaf Hering <ded022db89399a060a39da31922f173c6556c2d9@aepfle.de>
Cc: Jim Fehlig <39929b5b86d72d51fceac59b52303e3fe8a3083e@suse.com>

nertpinx/libvirt,agx/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,crobinso/libvirt,jfehlig/libvirt,olafhering/libvirt,andreabolognani/libvirt,olafhering/libvirt,eskultety/libvirt,rlaager/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,zippy2/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,rlaager/libvirt,datto/libvirt,fabianfreyer/libvirt,datto/libvirt,taget/libvirt,zippy2/libvirt,rlaager/libvirt,VenkatDatta/libvirt,taget/libvirt,libvirt/libvirt,agx/libvirt,crobinso/libvirt,taget/libvirt,jfehlig/libvirt,datto/libvirt,taget/libvirt,crobinso/libvirt,libvirt/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,datto/libvirt,taget/libvirt,VenkatDatta/libvirt,agx/libvirt,zippy2/libvirt,olafhering/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,nertpinx/libvirt,crobinso/libvirt,eskultety/libvirt,eskultety/libvirt,nertpinx/libvirt,eskultety/libvirt,nertpinx/libvirt,jardasgit/libvirt,rlaager/libvirt,datto/libvirt,rlaager/libvirt,libvirt/libvirt,jfehlig/libvirt,andreabolognani/libvirt,agx/libvirt,agx/libvirt,jfehlig/libvirt,zippy2/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,libvirt/libvirt,olafhering/libvirt,eskultety/libvirt