Temporarily remove Ceilometer installation

Ceilometer installation seems to be the cause of POST_FAILURE,
so this patch remove it temporarily.

Related error
https://zuul.opendev.org/t/openstack/build/5abe3c88e63249d0a6ad5bd764a9d604

Ceilometer installation was removed before, because Gnocchi
installation was failed. [1]
After above error was resolved, we reverted Ceilometer
installation. [2]
However, the tests using Ceilometer do not succeed as mentioned
at the beginning of this commit message.

[1] https://review.opendev.org/#/c/751965/
[2] https://review.opendev.org/#/c/754882/

Change-Id: I5c6ddd31abd58fa2941a3a1919f09f473dfd836e

.zuul.yaml

@@ -50,7 +50,10 @@
       # Temporarily remove because of Ubuntu Focal Migration issue
       #   https://storyboard.openstack.org/#!/story/2007732
       # - openstack/barbican
-      - openstack/ceilometer
+      # Temporarily remove because of Ubuntu Focal Migration issue
+      #   https://storyboard.openstack.org/#!/story/2008121
+      #   https://review.opendev.org/#/c/752294/
+      # - openstack/ceilometer
       - openstack/heat
       - openstack/mistral
       - openstack/mistral-dashboard
@@ -85,7 +88,10 @@
           heat: https://opendev.org/openstack/heat
           networking-sfc: https://opendev.org/openstack/networking-sfc
           aodh: https://opendev.org/openstack/aodh
-          ceilometer: https://opendev.org/openstack/ceilometer
+          # Temporarily remove because of Ubuntu Focal Migration issue
+          #   https://storyboard.openstack.org/#!/story/2008121
+          #   https://review.opendev.org/#/c/752294/
+          # ceilometer: https://opendev.org/openstack/ceilometer
           # Temporarily remove because of Ubuntu Focal Migration issue
           #   https://storyboard.openstack.org/#!/story/2007732
           # barbican: https://opendev.org/openstack/barbican

bindep.txt

@@ -3,12 +3,8 @@
 
 gettext [test]
 
-# Use mariadb instead of mysql
-# related to https://review.opendev.org/#/c/752294/
-#mysql-client [platform:dpkg]
-#mysql-server [platform:dpkg]
+mysql-client [platform:dpkg]
+mysql-server [platform:dpkg]
 postgresql
 postgresql-client [platform:dpkg]
 postgresql-server [platform:rpm]
-mariadb [platform:rpm]
-mariadb-server