Description of problem:
Need to expose 'virDomainSnapshotListChildrenNames' API in python binding. 

Version-Release number of selected component (if applicable):
libvirt-python-0.9.8-1.el6.x86_64

How reproducible:
always

Steps to Reproduce:
1. define a guest with qcow2 image
2. create a snapshot for the guest
3. run interact python to try libvirt python API

# qemu-img create -f qcow2 /var/lib/libvirt/images/disk.img 100M
Formatting '/var/lib/libvirt/images/disk.img', fmt=qcow2 size=104857600 encryption=off cluster_size=65536

# cat > /root/demo.xml <<EOF
<domain type='qemu'>
  <name>demo</name>
  <memory>219200</memory>
  <vcpu>1</vcpu>
  <os>
    <type arch='x86_64'>hvm</type>
    <boot dev='hd'/>
  </os>
  <devices>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/var/lib/libvirt/images/disk.img'/>
      <target dev='vda' bus='virtio'/>
    </disk>
    <input type='mouse' bus='ps2'/>
    <graphics type='spice' autoport='yes' listen='0.0.0.0'/>
  </devices>
</domain>
EOF

# virsh define /root/demo.xml
Domain demo defined from /root/demo.xml

# virsh snapshot-list demo
 Name                 Creation Time             State
------------------------------------------------------------

# virsh snapshot-create-as demo
Domain snapshot 1323685119 created

# virsh snapshot-list demo --descendants
 Name                 Creation Time             State
------------------------------------------------------------
 1323685119           2011-12-12 18:18:39 +0800 shutoff

# python
Python 2.6.6 (r266:84292, Sep 12 2011, 14:03:14) 
[GCC 4.4.5 20110214 (Red Hat 4.4.5-6)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import libvirt
>>> con = libvirt.open(None)
>>> dom_name = con.listDefinedDomains()[0]
>>> dom = con.lookupByName(dom_name)
>>> snap_name = dom.snapshotListNames(0)[0]
>>> snap = dom.snapshotLookupByName(snap_name, 0)
>>> dir(snap)
['__del__', '__doc__', '__init__', '__module__', '_dom', '_o', 'delete', 'domain', 'getConnect', 'getDomain', 'getName', 'getParent', 'getXMLDesc', 'listChildrenNames', 'numChildren']
>>> snap.getName()
'1323685119'
>>> snap.getDomain().name()
'demo'
>>> snap.listChildrenNames(0)

Actual results:

>>> snap.listChildrenNames(0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 3733, in listChildrenNames
    ret = libvirtmod.virDomainSnapshotListChildrenNames(self._o, flags)
AttributeError: 'module' object has no attribute 'virDomainSnapshotListChildrenNames'

Expected results:
fix it.

Additional info:

# nm -a -D /usr/lib64/python2.6/site-packages/libvirtmod.so |grep virDomainSnapshotNumChildren
000000000001d720 T libvirt_virDomainSnapshotNumChildren
                 U virDomainSnapshotNumChildren

# nm -a -D /usr/lib64/python2.6/site-packages/libvirtmod.so |grep virDomainSnapshotListChildrenNames

Note: nothing return in here.


In addition, it seems libvirt has exposed this c API, please see this commit:
http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=f2013c9dd1ce468b8620ee35c232a93ef7026fb0