RFR: JDK-8026245,,InetAddress.getLocalHost crash if IPv6 disabled (macosx)

[Rob McKenna]

Hi folks,

Looking for a review for the following:

http://cr.openjdk.java.net/~robm/8026245/webrev.01/

It seems there were a number of issues with the original fix for 
7180557. This patch resolves those:

- No existing net tests exercised the ipv4 only codepath
- the extern to lookupIfLocalhost was in the wrong place
- as a result of the prior review the call to lookupIfLocalhost was 
moved to below the call to getaddrinfo. It was then decided to move it 
back. Unfortunately the if (error) block was left in.

     -Rob