Drop the requirements on dbus-glib as the project was migrated to GDBus
./libdbusmenu-16.04.0/ChangeLog:2359: * Porting from dbus-glib to GDBus
./libdbusmenu-16.04.0/ChangeLog:2442: * Porting from dbus-glib to GDBus
./libdbusmenu-16.04.0/ChangeLog:2488: * Porting from dbus-glib to GDBus
./libdbusmenu-16.04.0/ChangeLog:8438: Add a single include file for dbus-glib
./libdbusmenu-16.04.0/ChangeLog:8611: Switching from dbus-glib to GDBus
./libdbusmenu-16.04.0/ChangeLog:8891: More name grabbing porting from dbus-glib to GDBus
./libdbusmenu-16.04.0/ChangeLog:8911: Switching to GDBus from dbus-glib
./libdbusmenu-16.04.0/ChangeLog:8919: Taking out the dbus-glib specialized types for now
./libdbusmenu-16.04.0/ChangeLog:9131: Dropping dbus-glib from the build requirements