dhclient-script: backport upstream changes

dhclient-script

@@ -186,9 +186,19 @@ make_resolv_conf() {
             echo "options ${RES_OPTIONS}" >> ${rscf}
         fi
 
+        shopt -s nocasematch 
         for nameserver in ${new_dhcp6_name_servers} ; do
-            echo "nameserver ${nameserver}" >> ${rscf}
+            # If the nameserver has a link-local address
+            # add a <zone_id> (interface name) to it.
+            if  [[ "$nameserver" =~ ^fe80:: ]]
+            then
+                zone_id="%${interface}"
+            else
+                zone_id=
+            fi
+            echo "nameserver ${nameserver}$zone_id" >> ${rscf}
         done
+        shopt -u nocasematch 
 
         change_resolv_conf ${rscf}
         rm -f ${rscf}