NO-JIRA: Strengthen test code so that server is always stopped regardless of previous exception(s). Specifically, this avoids the "Address already in use" spurious test failures that we are currently seeing immediately after testSendBogus fails.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1462458 13f79535-47bb-0310-9956-ffa450edef68