CAMEL-6117: Allow empty system_type

git-svn-id: https://svn.apache.org/repos/asf/camel/branches/camel-2.10.x@1461666 13f79535-47bb-0310-9956-ffa450edef68
CAMEL-6117: Allow empty service_type and system_type

git-svn-id: https://svn.apache.org/repos/asf/camel/branches/camel-2.10.x@1461668 13f79535-47bb-0310-9956-ffa450edef68