dbus: fix for read-only rootfs

Similar to how it's handled by avahi - Make sure /var/lib/dbus is a
symlink to /tmp/dbus.

package/dbus/S30dbus

@@ -16,6 +16,7 @@
 # Create needed directories.
 [ -d /var/run/dbus ] || mkdir -p /var/run/dbus
 [ -d /var/lock/subsys ] || mkdir -p /var/lock/subsys
+[ -d /tmp/dbus ] || mkdir -p /tmp/dbus
 
 RETVAL=0
 

package/dbus/dbus.mk

@@ -52,6 +52,8 @@ $(eval $(call AUTOTARGETS,package,dbus))
 
 $(DBUS_HOOK_POST_INSTALL): $(DBUS_TARGET_INSTALL_TARGET)
 	rm -rf $(TARGET_DIR)/usr/lib/dbus-1.0
+	rm -rf $(TARGET_DIR)/var/lib/dbus
+	ln -sf /tmp/dbus $(TARGET_DIR)/var/lib/dbus
 	$(INSTALL) -m 0755 package/dbus/S30dbus $(TARGET_DIR)/etc/init.d
 	touch $@