Description of problem:
Failed to run vm with NumaNode

Version-Release number of selected component (if applicable):
vdsm-4.16.1-0.gita4d9abf.el6.x86_64

How reproducible:
Always

Steps to Reproduce:
1. Create new vm and add via REST to vm numa node:
<vm_numa_node>
<index>0</index>
<memory>1024</memory>
<cpu>
<cores>
<core index="0"/>
<core index="1"/>
</cores>
</cpu>
</vm_numa_node>
2. Run vm
3.

Actual results:
Vm failed to run with exception in vdsm.log
Traceback (most recent call last):
  File "/usr/share/vdsm/virt/vm.py", line 2235, in _startUnderlyingVm
    self._run()
  File "/usr/share/vdsm/virt/vm.py", line 3255, in _run
    domxml = hooks.before_vm_start(self._buildCmdLine(), self.conf)
  File "/usr/share/vdsm/virt/vm.py", line 3045, in _buildCmdLine
    domxml.appendCpu()
  File "/usr/share/vdsm/virt/vm.py", line 931, in appendCpu
    self.conf.get('guestNumaNodes'), key=itemgetter('nodeIndex'))
KeyError: 'nodeIndex'


Expected results:
Vm success to run without any exceptions

Additional info:
If I change line:
guestNumaNodes = sorted(
                self.conf.get('guestNumaNodes'), key=itemgetter('nodeIndex'))
to 
guestNumaNodes = self.conf.get('guestNumaNodes') and restart vdsm all works fine