Fix for 2977 : exception during the Replication Server database trimming

The database appears to throw deadlock exception during the trimming process.
Since the updates to the replication log are only of two types :
 - add of record at the tail of the log
 - delete of record at the head of the log
It does not seem possible to have real deadlock, therefore this exception is 
probably thrown because the current value of the TXN timeout (500 msec) is
too short.

The fix is therefore simply to Increase this value to 10 seconds.

This should not have any performance impact.