mysql.conf: ensure InnoDB & UTF8

All databases should be UTF8 and InnoDB in Icehouse release. This commit
aims to configure MySQL having these values.
If we don't explicitly set the values, some OpenStack components would
fail to migrate databases (Neutron for example).

templates/database/mysql.conf.erb

@@ -2,6 +2,10 @@
 # Module:: cloud::database::sql
 #
 [mysqld]
+default-storage-engine          = innodb
+collation-server                = utf8_general_ci
+init-connect                    = 'SET NAMES utf8'
+character-set-server            = utf8
 max_connections                 = 1000
 skip_name_resolve               = 1
 connect_timeout                 = 5