Plugin multibandwidth: proper handling of invalid values

plugins/network/multibandwidth

@@ -109,6 +109,7 @@ for host in $hosts; do
         elif echo "$SPEED" | grep -q "G"; then
                 RATE=$(echo "$SPEED" | awk '{ print int($1 * 1024 * 1024 * 1024); }')
         else
+                RATE="U"
                 echo "Error: no data (timeout)" >&2
         fi
         if [ "$RATE" -gt "$max_mbps" ]; then