[libvirt] [PATCH 0/4] Updated patches 2-6 - virInterface test driver and netcf backend

[Laine Stump]

These patches correspond to patches 2-6 in the set I sent yesterday
(the 1st and 2nd had no changes, so they stand as-is). They
incorporate all changes brought up in review of the first set. In
particular:

1) When looking for a cached virInterface object for an interface, I
now check that the mac address being searched for matches the one in
the virInterface (case insensitive comparison). If it doesn't match, I
create a new object rather than trying to modify the existing object
with the same interface name, as that could have led to "improper
behavior".

2) in virInterfaceFindByMACString() I now follow danpb's suggestion
and use continue, rather than getting fancy with booleans.

3) testinterfaceCreate() and testInterfaceDestroy() now check if the
interface has already been created/destroyed, and won't do the same
operation twice in a row.

4) in the netcf backend driver, I now "roundtrip" the xml data in both
interfaceDefineXML() and interfaceGetXMLDesc().