SOLR-3854: Cleans up a lot of the tests by using a common function to build a consistent schemed URL (fixes SSL for SolrCmdDistributorTest) + disabled the "useClientAuth" property for OSX clients.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1567643 13f79535-47bb-0310-9956-ffa450edef68