Sheepdog and possibly others use nested objects for network server and
thus could be specified in a way that libvirt would not parse.
Validates that https://bugzilla.redhat.com/show_bug.cgi?id=1464821
is fixed properly.
If a value of the first level object contains more objects needing
deflattening which would be wrapped in an actual object the function
would not recurse into them.
By this simple addition we can fully deflatten the objects.
As it turns out sometimes users pass in an arbitrarily nested structure
e.g. for the qemu backing chains JSON pseudo protocol. This new
implementation deflattens now a single object fully even with nested
keys.
Additionally it's not necessary now to stick with the "file." prefix for
the properties.
