Remove transaction and query locks. Since DB instances are stored in a volatile attributes on ZMySQLDA instances, they are bound to one thread at most, so it's not needed to handle concurent accesses, and removing them should induce a performance increase.
Remove a tabulation caracter.
Delete volatile attribute at transaction end (_finish and _abort) to avoid multiple threads from using the same connection - because of ZODB connection pooling.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@13629 20353a03-c40f-0410-a6d1-a30d3c3de9de