liboil: convert old-style hook to new-style hook

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/liboil/liboil.mk

@@ -35,9 +35,10 @@ endif
 
 LIBOIL_DEPENDENCIES = $(LIBOIL_GLIB_DEP)
 
-$(eval $(call AUTOTARGETS,package,liboil))
-
-$(LIBOIL_HOOK_POST_INSTALL):
-	# Remove useless bugreport program from the target
+define LIBOIL_TARGET_CLEANUP
 	rm -f $(TARGET_DIR)/usr/bin/oil-bugreport
-	touch $@
+endef
+
+LIBOIL_POST_INSTALL_TARGET_HOOKS += LIBOIL_TARGET_CLEANUP
+
+$(eval $(call AUTOTARGETS,package,liboil))