meta-phosphor: prep for new override syntax

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I588025b614416c43aa2d053765ab53bacf890cb5
diff --git a/meta-phosphor/classes/image_version.bbclass b/meta-phosphor/classes/image_version.bbclass
index a4b4c3d..56ebe66 100644
--- a/meta-phosphor/classes/image_version.bbclass
+++ b/meta-phosphor/classes/image_version.bbclass
@@ -1,6 +1,6 @@
 # Base image version class extension
 
-DEPENDS_append = " os-release"
+DEPENDS:append = " os-release"
 
 def do_get_version(d):
     import configparser