CI: Enable fluentd in MariaDB jobs

Since fluentd is disabled in MariaDB jobs - haproxy logs are not getting
populated.

Change-Id: I56b3fc1be6940d97905cdb2c4452b846f106c071
Depends-on: https://review.opendev.org/713704

tests/templates/globals-default.j2

@@ -98,7 +98,7 @@ enable_cells: "yes"
 
 {% if scenario == "mariadb" %}
 enable_chrony: "no"
-enable_fluentd: "no"
+enable_fluentd: "yes"
 enable_mariadb: "yes"
 enable_memcached: "no"
 enable_rabbitmq: "no"

tools/setup_gate.sh

@@ -61,7 +61,7 @@ function setup_config {
     fi
 
     if [[ $SCENARIO == "mariadb" ]]; then
-        GATE_IMAGES="^cron,^haproxy,^keepalived,^kolla-toolbox,^mariadb"
+        GATE_IMAGES="^cron,^fluentd,^haproxy,^keepalived,^kolla-toolbox,^mariadb"
     fi
 
     # NOTE(yoctozepto): we cannot build and push at the same time on debian