Install python3-protobuf and gstreamer1.0-plugins-ugly.

Both packages are required for real time video streaming as a part
of OOBE. x264enc is only included in ugly gstreamer plugins.

Change-Id: I297874e3c44f4206ebd6fb3031145bfbccee4b44
diff --git a/preamble.mk b/preamble.mk
index 26e188b..9d943e0 100644
--- a/preamble.mk
+++ b/preamble.mk
@@ -116,6 +116,7 @@
 	python3-jwt \
 	python3-numpy \
 	python3-pip \
+	python3-protobuf \
 	python3-reportbug \
 	python3-setuptools \
 	python3-wheel \
diff --git a/rootfs.mk b/rootfs.mk
index f46be03..990306e 100644
--- a/rootfs.mk
+++ b/rootfs.mk
@@ -42,6 +42,7 @@
 	gstreamer1.0-plugins-base \
 	gstreamer1.0-plugins-base-apps \
 	gstreamer1.0-plugins-good \
+	gstreamer1.0-plugins-ugly \
 	gstreamer1.0-tools \
 	libdrm2 \
 	libgstreamer1.0-0 \