MySQL 5.5.19

# Bugs Fixed
* InnoDB Storage Engine: An incorrect deadlock could occur on a server doing a substantial amount of change buffering for DML operations, particularly DELETE statements.
* Rounding DBL_MAX returned DBL_MAX, not 'inf'.
* mysql_upgrade did not upgrade the system tables or create the mysql_upgrade_info file when run with the --write-binlog or --skip-write-binlog option.
* If a plugin was uninstalled, thread local variables for plugin variables of string type with wth PLUGIN_VAR_MEMALLOC flag were not freed.
* Deadlock could occur when these four things happened at the same time: 1) An old dump thread was waiting for the binary log to grow. 2) The slave server that replicates from the old dump thread tried to reconnect. During reconnection, the new dump thread tried to kill the old dump thread. 3) A KILL statement tried to kill the old dump thread. 4) An INSERT statement caused a binary log rotation.