Replaces packets_dropped nfvi metric for packets_in_dropped and packets_out_dropped

Change-Id: I139a275f0d758385673d177724086fe23465fc2e
Signed-off-by: Benjamin Diaz <bdiaz@whitestack.com>
diff --git a/models/yang/mano-types.yang b/models/yang/mano-types.yang
index df29868..7784d5c 100644
--- a/models/yang/mano-types.yang
+++ b/models/yang/mano-types.yang
@@ -692,7 +692,8 @@
       enum disk_write_bytes;
       enum packets_sent;
       enum packets_received;
-      enum packets_dropped;
+      enum packets_in_dropped;
+      enum packets_out_dropped;
     }
   }