Update README-VTN.md

add -y to the apt-get install
diff --git a/xos/configurations/cord/README-VTN.md b/xos/configurations/cord/README-VTN.md
index 348aca6..d585d5c 100644
--- a/xos/configurations/cord/README-VTN.md
+++ b/xos/configurations/cord/README-VTN.md
@@ -8,11 +8,14 @@
 
     # set ONOS_VTN_HOSTNAME to the host where the VTN container was installed
     ONOS_VTN_HOSTNAME="cp-2.smbaker-xos5.xos-pg0.clemson.cloudlab.us"
-    apt-get install python-pip
+    apt-get -y install python-pip
     pip install -U setuptools pip
     git clone https://github.com/openstack/networking-onos.git
     cd networking-onos
-    sudo python setup.py install
+    python setup.py install
+    # the above fails the first time with an error about pbr.json
+    # I ran it again and it succeeded, but I am skeptical there's
+    # not still an issue lurking...
     cat > /usr/local/etc/neutron/plugins/ml2/conf_onos.ini <<EOF
     [ml2_onos]
     url_path = http://$ONOS_VTN_HOSTNAME:8181/onos/vtn
@@ -39,4 +42,4 @@
 VTN doesn't seem to like cloudlab's networks (flat-net-1, ext-net, etc). You might have to delete them all.
 
 For development, I suggest using the bash configuration (remember to start the ONOS observer manually) so that 
-there aren't a bunch of preexisting Neutron networks and nova instances to get in the way. 
\ No newline at end of file
+there aren't a bunch of preexisting Neutron networks and nova instances to get in the way.