isolated network metadata does not work with nvp plugin

[Aaron Rosen]

The following if statement prevents metadata from working with nvp if a network is isolated.

if (self.conf.enable_isolated_metadata and
     self.conf.use_namespaces and
     not self.conf.enable_metadata_network):

[Salvatore Orlando (salvatore-orlando)]

Manually setting to fix committed as the commit msg did not have reference to bug.
My bad for approving the patch without realising it.