meta-ibm: prep for new override syntax

Change-Id: I9116ed7260e369136acb39eec15075db2d4dbeba
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/meta-ibm/meta-romulus/recipes-phosphor/images/obmc-phosphor-image.bbappend b/meta-ibm/meta-romulus/recipes-phosphor/images/obmc-phosphor-image.bbappend
index ccf7b45..ef87ad8 100644
--- a/meta-ibm/meta-romulus/recipes-phosphor/images/obmc-phosphor-image.bbappend
+++ b/meta-ibm/meta-romulus/recipes-phosphor/images/obmc-phosphor-image.bbappend
@@ -1 +1 @@
-OBMC_IMAGE_EXTRA_INSTALL_append_romulus = " mboxd liberation-fonts uart-render-controller"
+OBMC_IMAGE_EXTRA_INSTALL:append:romulus = " mboxd liberation-fonts uart-render-controller"