LACNIC tests failing

The tests for this module use a randomly-selected RIR, to ensure that the tests cover all the RIRs over time without the high overhead of testing all the RIRs every time.

But since 7 May, tests that select LACNIC have been failing because LACNIC changed the name of one of the files used to store registry data. I don't know if this was intentional or not, and I don't know whether or not this will change back. (Changes are very infrequent, so I don't expect something to happen immediately either way.)

I'm posting a patch here for anyone who uses LACNIC. I am also committing this patch so that the Drupal testbot tests will continue to work. If in the future LACNIC changes back to how it used to work (and how all the other registries work) then this patch may also be useful to allow you to reverse the fix.