meta-phosphor: prep for new override syntax

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I588025b614416c43aa2d053765ab53bacf890cb5
diff --git a/meta-phosphor/classes/obmc-phosphor-image.bbclass b/meta-phosphor/classes/obmc-phosphor-image.bbclass
index c83dce3..80c16d2 100644
--- a/meta-phosphor/classes/obmc-phosphor-image.bbclass
+++ b/meta-phosphor/classes/obmc-phosphor-image.bbclass
@@ -70,7 +70,7 @@
 # FIXME: phosphor-net-ipmi depends on phosphor-ipmi-host !?!? and
 # cannot be built on core-qemu machines because of the dependency
 # tree under phosphor-ipmi-host
-FEATURE_PACKAGES_obmc-net-ipmi_qemuall = ""
+FEATURE_PACKAGES_obmc-net-ipmi:qemuall = ""
 
 # Add new packages to be installed to a package group in
 # packagegroup-obmc-apps, not here.