* qt/dbus/Makefile.am: New file.  Fix "make dist", add all
        headers required during build to EXTRA_DIST.
        * qt/src/Makefile.am: Fix "make dist", add 'qdbus.h' to
        EXTRA_DIST.
        * qt/Makefile.am: Fix "make dist", add 'dbus' to DIST_SUBDIRS.
        * configure.in: Fix "make dist", take care that the Makefile
        for qt/dbus is being generated.