Create mysql user for non-ha deployments
Create mysql user for non-ha deployments

Currently health check for mysql container reports unhealthy container
because there is no 'mysql' user created. This patch creates the user
during mysql_bootstrap without any permission, just to allow health
check to connect to DB and run 'select 1'.

Change-Id: Iab26da0d30939b219189d4e7beb2a61d456ab7c3
Closes-Bug: #1718944

dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates,openstack/tripleo-heat-templates