QPID-5719: Fix unintentional dependency on qpid-ha for non-HA installations.

qpidd init script should not use qpid-ha if it is not installed.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1590777 13f79535-47bb-0310-9956-ffa450edef68