Description of problem:
Monitor device_add with a driver name argument that identifies a
Steps to Reproduce:
1. qemu-kvm -nodefaults -S -display none -monitor stdio
2. device_add rng-egd
qdev-monitor.c:491:qdev_device_add: Object 0x7f3ee1e74900 is not an instance of type device
The command fails cleanly with an error message such as "'rng-egd' is
not a valid device model name".
Fixed upstream in commit 061e84f.
Fix has been folded into the fix for bug 669524.
*** This bug has been marked as a duplicate of bug 669524 ***