neustardb: skip if all fields of interest are null
neustardb: skip if all fields of interest are null

Summary: Since we only care about proxies for the time being, why process all the data? Why not skip non-proxies?

Test Plan:
Output is still the same before and after

Before:
Running the first two steps on the full dataset on my laptop took 50:35.91

After:
Running the first two steps on the full dataset on my laptop took only 11:59.89 (yes, less than 12 minutes)

Reviewers: ashalabi

Reviewed By: ashalabi

Subscribers: dev

Differential Revision: https://phab.duosec.org/D7587

git-svn-id: f4d3965f88d1c4649b3a56f994ec502c1935526e@26986 83f8c0fa-5cd7-49b8-a9ad-5e47a2db8e72

duo-labs/neustar2mmdb,duo-labs/neustar2mmdb