meta-ibm: prep for new override syntax

Change-Id: I9116ed7260e369136acb39eec15075db2d4dbeba
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/meta-ibm/recipes-phosphor/interfaces/bmcweb_%.bbappend b/meta-ibm/recipes-phosphor/interfaces/bmcweb_%.bbappend
index a45f048..659eafd 100644
--- a/meta-ibm/recipes-phosphor/interfaces/bmcweb_%.bbappend
+++ b/meta-ibm/recipes-phosphor/interfaces/bmcweb_%.bbappend
@@ -1,4 +1,4 @@
-EXTRA_OEMESON_append = " \
+EXTRA_OEMESON:append = " \
     -Dinsecure-tftp-update=enabled \
     -Dibm-management-console=enabled \
 "