qdev_prop_set_* functions are always called by machine init functions
that should know what they're doing, so they abort on error.  Still,
an assert(!errp) does not aid debugging.  Print an error before aborting.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>