Description of problem:
Try adjusting a kvm guests RAM allocation.

Version-Release number of selected component (if applicable):
libvirt-0.3.1-2.fc7.x86_64

How reproducible:
Always.

Steps to Reproduce:
1. Run virt-manager
2. Try adjusting RAM for an existing KVM guest.
  
Actual results:
[jon@damaestro ~]$ virt-manager 
libvir: error : this function is not supported by the hypervisor:
virDomainSetMaxMemory
Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/details.py", line 448, in
config_memory_apply
    self.vm.set_max_memory(memory*1024)
  File "/usr/share/virt-manager/virtManager/domain.py", line 626, in set_max_memory
    self.vm.setMaxMemory(memory)
  File "/usr/lib64/python2.5/site-packages/libvirt.py", line 321, in setMaxMemory
    if ret == -1: raise libvirtError ('virDomainSetMaxMemory() failed', dom=self)
libvirt.libvirtError: virDomainSetMaxMemory() failed this function is not
supported by the hypervisor: virDomainSetMaxMemory

Expected results:
RAM allocation changes or is not offered as being able to change.

Additional info: