This modifies the formatting function of virInterface to be a proper
mirror of the parse function, including the addition of a
"parentIfType" arg so that we can decide whether or not it is
appropriate to emit the elements that are only in toplevel interfaces,
as well as the <link> element (which isn't allowed for bridge
interfaces).
Since the restructuring of the code necessarily changes the order of
some of the elements, some test case data had to be updated.
The interface state for bonds and vlans does seem to reflect the state
of the underlying physical devices, at least in some cases, so it
makes sense to allow reporting it (netcf now does).
The link state/speed for bridge devices is meaningless though, so we
don't even look for it.
* docs/schemas/interface.rng: schemas for the interface XML files
directly imported from netcf-0.1.0
* tests/interfaceschemadata/*.xml: set of test files from netcf-0.1.0
changed to use single quote instead of double quote
