Avoid using sed -i option.

- BSD sed and GNU sed behaves differently.

Change-Id: I36c7c1f1eb6bd678811e103b651bfd87da454664
diff --git a/onos.sh b/onos.sh
index 0790afd..a8bcb49 100755
--- a/onos.sh
+++ b/onos.sh
@@ -416,8 +416,7 @@
     else
       echo $line
     fi
-  done < ${ZK_CONF_TEMPLATE} > ${temp_zk}
-  sed -e "s|__CLIENTPORT__|${ZK_CLIENTPORT}|" -i "" ${temp_zk}
+  done < ${ZK_CONF_TEMPLATE} | sed -e "s|__CLIENTPORT__|${ZK_CLIENTPORT}|" > ${temp_zk}
   
   end-conf-creation ${ZK_CONF}