always rollsback.

The global variable max_binlog_cache_size cannot be set more than 4GB on
32 bit systems, limiting transactions of all storage engines to 4G of changes.

The problem is max_binlog_cache_size is declared as ulong which is 4 bytes
on 32 bit and 8 bytes on 64 bit machines.

Fixed by using ulonglong for max_binlog_cache_size which is 8bytes on 32 
and 64 bit machines.The range for max_binlog_cache_size on 32 bit and 64 bit
systems is 4096-18446744073709547520 bytes.