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/chassis/obmc-op-control-power_%.bbappend b/meta-ibm/recipes-phosphor/chassis/obmc-op-control-power_%.bbappend
index 72d991c..4fc41d0 100644
--- a/meta-ibm/recipes-phosphor/chassis/obmc-op-control-power_%.bbappend
+++ b/meta-ibm/recipes-phosphor/chassis/obmc-op-control-power_%.bbappend
@@ -1 +1 @@
-FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"