longmessagebuffer' error"), and a set of other issues related to the
pool of "Fired Trigger" records.

When exhausting the fired triggers pool, cluster wrongly issues the error
message 218 (Out of LongMessageBuffer). This commit adds a new error code
(221) for that situation. In addition, the commit fixes one more case where
218 may wrongly be reported.
Other issues fixed by this commit:

* Setting low values for MaxNoOfFiredTriggers trigers an error in DLMHashTable
template. The DLMHashTable fails to allocate memory if there is just one hash 
bucket.

* This commit ensures that a transaction releases any "fired trigger" records
it holds when it aborts. Earlier, these records would be held until the 
ApiConnectRecord was reused by another transaction.

* For the "Fired Trigger" pool in ndbinfo.ndb$pools, 'high' would always equal 
'total'. This was beacuse all records were momentarily seized when initializing them.
This commit fixes that, so that 'high' gives the maximal value *after*
initialization.