Removed bad assert in AccessGroupGarbageTracker
Added better error state capture to rangeserver-failover-basic tests
Fixed future/scanner/mutator close order problem causing ThriftBroker crash
issue 1226: Fixed race condition in LocalBroker::readdir()
issue 1227: Fixed readhead problem in IntervalScannerAsync client lib class
issue 1237: Fix stack corruption bug in dump table logic
issue 1242: Fixed state init problem in AccessGroupGarbageTracker
Upgraded for 0.9.7.18 release