Disable gobject-introspection to make openbmc build on ppc64le

As a known issue, the introspection data cannot be built on ppc64le.
https://lists.yoctoproject.org/pipermail/yocto/2016-April/029582.html.
To work around, I disable the use of qemu when we build openbmc
by modifying the configuration files:
Add

MACHINE_FEATURES_BACKFILL_CONSIDERED = "qemu-usermode"

to the end line.

Resolve: openbmc/openbmc#640

Change-Id: Idb6584ca43a8d4f005aa365f62aa1d46d2a00fd5
Signed-off-by: Nan Li <william.bjlinan@hotmail.com>
diff --git a/meta-phosphor/conf/local.conf.sample b/meta-phosphor/conf/local.conf.sample
index 9af90ee..15e3243 100644
--- a/meta-phosphor/conf/local.conf.sample
+++ b/meta-phosphor/conf/local.conf.sample
@@ -19,3 +19,5 @@
 EXTRA_USERS_PARAMS = " \
   usermod -p '\$1\$UGMqyqdG\$FZiylVFmRRfl9Z0Ue8G7e/' root; \
   "
+MACHINE_FEATURES_BACKFILL_CONSIDERED = "qemu-usermode"
+