simpleleveldb: dump_csv properly cleaned up for keep-alive connections
simpleleveldb: dump_csv properly cleaned up for keep-alive connections

consider the close connection callback an error condition, so clean
up manually when the request is fulfilled and cancel the callback

this problem is exacerbated by libevent-1.4 failing to notice when
keep-alive http connections close

also bump simpleleveldb version

jmptrader/simplehttp,jtsui/leveldb-daemon,jtsui/leveldb-daemon,jtsui/leveldb-daemon,bitly/simplehttp,jmptrader/simplehttp,jmptrader/simplehttp,bitly/simplehttp,bitly/simplehttp