Raise Twitter MySQL version to 5.5.35.t15
MYSQL-355: Add option to disable deadlock detection

Deadlock detection code can be performance critical under heavily
concurrent workload. Add an option innodb_deadlock_check (default
ON as current behaviour).
Write query throttling and general qeury throttling (IM-1108)

To avoid backing up of backlogs inside innodb concurrency queue,
we have to throttle threads executing queries at MySQL query
level. In Gizzard databases, mysql status variable
thread_running gives approximate number of active queries and
we leverage it as general throttling control.

A new option twitter_query_throttling_limit [0,10000] is added
as tunable parameter. A new error ER_QUERY_THROTTLED is thrown
if running threads exceed twitter_query_throttling_limit.

Additionallu, we may want to throttle concurrent wrties only.
A new option twitter_write_throttling_limit [0, 5000] is added
as configurable to control how many writes allowed in mysql
server. The same ER_QUERY_THROTTLED is thrown if write queries
exceeding twitter_query_throttling_limit. A value zero means
no throttling. A new status variable Write_queries_running is
added to track currently running writes and it is used for
throttling.

Four new status variables are added to monitor workload,
Read_queries, Write_queries, Total_queries_rejected,
Write_queries_rejected, in addition to Write_queries_running.
Twitter MySQL 5.5.35.t15 release