Add general_log to mariadb container and make heka collect it

Added general_log to ansible/roles/mariadb/templates/galera.cnf.j2
to improve mariadb logging.

This will be helpful to debug mariadb issues especially when
mariadb is scaled.

Test results of this patch set are at:
http://paste.openstack.org/show/492852/

Change-Id: I80438d1bbdd1ed2a1f47489c6f9c45b8107340a0
Closes-Bug: #1563668

ansible/roles/common/templates/heka-mariadb.toml.j2

@@ -6,6 +6,6 @@ filename = "lua_decoders/os_mysql_log.lua"
 type = "LogstreamerInput"
 decoder = "mariadb_log_decoder"
 log_directory = "/var/log/kolla"
-file_match = 'mariadb/mariadb\.log\.?(?P<Seq>\d*)$'
+file_match = 'mariadb/(mariadb|mariadb-error)\.log\.?(?P<Seq>\d*)$'
 priority = ["^Seq"]
 differentiator = ['mariadb']

ansible/roles/mariadb/templates/galera.cnf.j2

@@ -3,7 +3,9 @@
 bind-address={{ hostvars[inventory_hostname]['ansible_' + api_interface]['ipv4']['address'] }}
 port={{ mariadb_port }}
 
-log-error=/var/log/kolla/mariadb/mariadb.log
+log-error=/var/log/kolla/mariadb/mariadb-error.log
+general_log=1
+general_log_file=/var/log/kolla/mariadb/mariadb.log
 
 binlog_format=ROW
 default-storage-engine=innodb