Add trace to integration gate scripts

The set -x enabled line-by-line tracing within a bash
script. This makes it easier to follow gate logs.

Change-Id: I7a164cf94f661929d96f2c3d41ec0d2ad1530e32

tools/gate/integration/post_test_hook.sh

@@ -2,9 +2,12 @@
 
 # This script will be executed inside post_test_hook function in devstack gate
 
+set -x
+
 cd /opt/stack/new/horizon
 sudo -H -u stack tox -e py27integration
 retval=$?
+
 if [ -d openstack_dashboard/test/integration_tests/integration_tests_screenshots/ ]; then
   cp -r openstack_dashboard/test/integration_tests/integration_tests_screenshots/ /home/jenkins/workspace/gate-horizon-dsvm-integration/
 fi

tools/gate/integration/pre_test_hook.sh

@@ -2,6 +2,8 @@
 
 # This script will be executed inside pre_test_hook function in devstack gate
 
+set -x
+
 cd /opt/stack/new/horizon/openstack_dashboard/local/local_settings.d
 mv _20_integration_tests_scaffolds.py.example _20_integration_tests_scaffolds.py
 sudo service apache2 restart