do not create keyspace if exists

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1491771 13f79535-47bb-0310-9956-ffa450edef68
add metadata-store-cassandra in deptMngt in top pom

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1491772 13f79535-47bb-0310-9956-ffa450edef68
exclude servlet-api

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1491773 13f79535-47bb-0310-9956-ffa450edef68
use dynamic ports for all cassandra ports

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1491774 13f79535-47bb-0310-9956-ffa450edef68