Move the random free port generate back into hbasecommontestingutility
from hbasetestingutility.
Add a create simple kdc server utility that will start a kdc server and
if a bindexception, create a new one on a new random port in hbase-common.
Add new BoundSocketMaker helpful when trying to manufacture
BindExceptions because of port clash.
Change thrift and http kdc tests to use this new utility (removes
code duplication around kdc server setup).