Fix 'ip -4 addr' command.

windows/scripts/ip

@@ -541,6 +541,7 @@ if [[ $object == "link" ]] ; then
 elif [[ $object == "addr" ]] ; then
 
     if [[ $command == "add" ]] || [[ $command == "del" ]] ; then
+        mask=$(prefix_to_netmask $(basename $1))
         address=$(dirname $1)
         shift
     elif [[ $command == "list" ]] ; then
@@ -554,6 +555,7 @@ elif [[ $object == "addr" ]] ; then
 
     if [[ "$opt_family" == "ipv4" || "$opt_family" == "" ]] ; then
         ipcmd="netsh interface ip $command address"
+        address="$address $mask"
     elif [[ "$opt_family" == "ipv6" ]] ; then
         ipcmd="netsh interface ipv6 $command address"
     else