classes: prepare some classes for native

Enable native recipes to inherit the following classes:
  skeleton-python
  skeleton-sdbus
  skeleton-gdbus
  dbus-dir
  obmc-phosphor-dbus-service

Change-Id: I1d79ffc38792dd48016f09119fc8ace46a304a4b
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/classes/obmc-phosphor-dbus-service.bbclass b/classes/obmc-phosphor-dbus-service.bbclass
index 68a42ce..4066c6c 100644
--- a/classes/obmc-phosphor-dbus-service.bbclass
+++ b/classes/obmc-phosphor-dbus-service.bbclass
@@ -30,7 +30,7 @@
 inherit dbus-dir
 inherit obmc-phosphor-utils
 
-RDEPENDS_${PN} += "dbus-perms"
+RDEPENDS_${PN}_append_class-target = " dbus-perms"
 DBUS_PACKAGES ?= "${PN}"
 
 _INSTALL_DBUS_CONFIGS=""