Remove libjack dependency on libdbus for mixed scenario; fix warning.

Warning is fixed by removing the static functions related to classic launch when libdbus launch is used.
For classic (jackd only) and mixed (jackd and jackdbus) scenarios we don't use libdbus for launching.
For jackdus only scenario, we use only libdbus.
So there is no change in classic and dbus scnearios. Change only affects the mixed scenario.

git-svn-id: http://subversion.jackaudio.org/jack/jack2/trunk/jackmp@3581 0c269be4-1314-0410-8aa9-9f06e86f4224