Code Review 6706251: api/java_net/NetworkInterface/index.html#misc: getDisplayName() returned non null but empty String

[Christopher Hegarty - Sun Microsystems Ireland]

Hi Michael,

This is a forward port of a fix that you did in JDK6u11 to JDK7. The 
source changes are trivial and the very same as what went in 6.

The change is for strict conformance of getDisplayName, should return 
null instead of an empty string.

Webrev:
  http://cr.openjdk.java.net/~chegar/6706251/webrev.00/webrev/

-Chris.