Add update step after enabling OpenStack repos

In specific cases, there may be conflicts between packages
provided by Centos and RDO repos. In that case RDO repos
should be used.

To avoid any of these issues, this patch updates packages
right after enabling the repos.

Note this will be required when gate jobs move to CentOS 7.3
because of conflicts between mariadb-libs in CentOS and
mariadb-common in RDO repos.

Change-Id: Icaeed8602378780f2c9bc8b22621c09b65bf95a8

run_tests.sh

@@ -138,6 +138,7 @@ echo "root hard nofile 65536" | $SUDO tee -a /etc/security/limits.conf
 if [ "${MANAGE_REPOS}" = true ]; then
     $SUDO curl -L ${DELOREAN} -o /etc/yum.repos.d/delorean.repo
     $SUDO curl -L ${DELOREAN_DEPS} -o /etc/yum.repos.d/delorean-deps.repo
+    $SUDO yum update -y
 fi
 
 # Install dependencies