deployment: try to retrieve network.yml via 'ngcpcfg pull'

this *might* fail due to ssh key setup, but we have to avoid
merge conflicts and therefore need to get ngcpcfg pull working...

From: Michael Prokop <mprokop@sipwise.com>

deployment.sh

@@ -1261,7 +1261,7 @@ if "$PRO_EDITION" ; then
     ngcpcfg commit 'deployed /etc/ngcp-config/network.yml'
     ngcpcfg build
   else # ROLE = sp2
-    cp /mnt/glusterfs/shared_config/network.yml /etc/ngcp-config/network.yml
+    ngcpcfg pull
     ngcpcfg build
   fi
 EOT