Qfs tools: change sequence number parameter type from int32_t to kfsSeq_t to make these consistent with other RPCs.
Meta server: use range truncate to implement "prune from head".[The only reason not to remove "prune from head" is that it can be trivially implemented by invoking range truncate.] Rework append logical EOF handling: always set EOF to the next chunk boundary, instead of attempting to use the actual last chunk size, in order to reduce the meta transaction log size / bandwidth, simplify range delete, and avoid possible last chunk info searches / retrieval attempts in order to calculate/update logical EOF. Append file are sparse by design, therefore using the same EOF handling / mechanism as with non / append "replicated" files doesn't make much sense: it doesn't serve any particular purpose, while increases complexity, and uses system resources (primarily cpu).