Fix NPE when logging network info for vvm sync.

When the network info for a network can't be fetched on a connectivity
callback, make sure that we don't crash when doing our logging. Null
networks are handled lower in the stack so we don't have to worry about
that.

Bug: 26407644
Change-Id: I3be367d84819f56f82b165fbe92d42dc4c82be16
1 file changed