DISPATCH-83: Error messages are not displayed if an error occurs when starting in deamon mode.

Examples:

$ qdrouterd -d -U xx
Daemon error: Can't look up user xx
$ qdrouterd -d -I xx
Daemon error: Cannot stat python library path 'xx'
$ qdrouterd -d -c xx
Daemon error: Exception: Cannot load configuration file xx: [Errno 2] No such file or directory: 'xx'
$ qdrouterd -d -P /xx
Daemon error: Can't write pidfile /xx

git-svn-id: https://svn.apache.org/repos/asf/qpid/dispatch/trunk@1644532 13f79535-47bb-0310-9956-ffa450edef68