Disable JVM DNS Caching if DNS server is link-local

[nebhale]

Currently, the DNS Caching in the JVM is controlled by either the JVM default (currently -1, FOREVER) or a user configuration. BOSH now exposes a DNS to the container that takes care of ttl caching for all requests, close to the application itself, so in systems where this DNS is available, the buildpack should disable the JVM's built in cache (0). To detect if this DNS is in place, the buildpack should determine if the current DNS for the container is at a link-local address.