Don't raise MySQL 2013 'Lost connection' errors
Don't raise MySQL 2013 'Lost connection' errors

Closes-bug: #1276510

Although this code error is part of the `ping_listener` tests, it was
missing from the list of known - and ignored - connection errors.

The code error 2013 refers to a connection lost during a query, see:
https://dev.mysql.com/doc/refman/5.0/en/error-messages-client.html#error_cr_server_lost

Without this error code, the session won't try to reconnect to mysql,
which makes `max_retries` useless.

Change-Id: I006fd3ae88dd7ab61f7f8811562fb78ce4a331ad

keedio/sahara,crobby/sahara,crobby/sahara,mapr/sahara,openstack/sahara,esikachev/scenario,bigfootproject/sahara,crobby/sahara,esikachev/scenario,matips/iosr-2015,tellesnobrega/storm_plugin,esikachev/sahara-backup,tellesnobrega/storm_plugin,citrix-openstack-build/sahara,tellesnobrega/sahara,ekasitk/sahara,tellesnobrega/storm_plugin,mapr/sahara,xme1226/sahara,zhangjunli177/sahara,tellesnobrega/sahara,henaras/sahara,esikachev/scenario,redhat-openstack/sahara,esikachev/sahara-backup,zhujzhuo/Sahara,egafford/sahara,xme1226/sahara,zhujzhuo/Sahara,esikachev/sahara-backup,citrix-openstack-build/sahara,henaras/sahara,bigfootproject/sahara,keedio/sahara,ekasitk/sahara,egafford/sahara,matips/iosr-2015,henaras/sahara,matips/iosr-2015,redhat-openstack/sahara,zhangjunli177/sahara,citrix-openstack-build/sahara,xme1226/sahara,bigfootproject/sahara,keedio/sahara,zhujzhuo/Sahara,openstack/sahara,zhangjunli177/sahara,ekasitk/sahara,redhat-openstack/sahara,mapr/sahara