Validate IP address ranges correctly on Alias Bulk Import

The code was there to attempt to validate and implement IP address range lines in Alias Bulk Import e.g.
10.20.0.0-10.21.22.0
should produce a bunch of smaller ranges with appropriate CIDRs.
This fixes the code so IP address ranges actually make it through into the resulting Alias.
Merge pull request #868 from phildd/master

Validate IP address ranges correctly on Alias Bulk Import