Right now, -mem-path will fall back to RAM-based allocation in some
cases.  This should never happen with "-object memory-file", prepare
the code by adding correct error propagation.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NHu Tao <hutao@cn.fujitsu.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

MST: drop \n at end of error messages