RFR (XS): 8162819: fix minor Javadoc issues and remove warnings in java.net.Socket and java.net.Inet*Address

[Langer, Christoph]

Hi,

please review these small fixes for Javadoc issues and removal of warnings.

Bug: https://bugs.openjdk.java.net/browse/JDK-8162819
Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8162819.1/

Thanks
Christoph