Switch set -x to set -e to disable output

This ps changes set -x to set -e in config.sh so that all the
commands will not throw in output

Change-Id: I08d2e56ea300509a3f579c888bfe6f1bd69deefd
Signed-off-by: Sreejith Punnapuzha <sreejith.punnapuzha@outlook.com>

tools/multi_nodes_gate/airship_gate/lib/config.sh

@@ -256,7 +256,7 @@ config_net_is_layer3() {
 config_netspec_for_role() {
   role="$1"
 
-  set -x
+  set -e
 
   for net in $(config_net_list)
   do