For ENG-4519, add cancellable watch to avoid double handling truncation requests
ENG-4571: If the snapshot doesn't have a digest file, it ain't a
snapshot.  Reject-a-rino.

r=nshi
Merge pull request #463 from VoltDB/ENG-4519

For ENG-4519, add cancellable watch to avoid double handling truncation requests
ENG-4576: When scanning snapshots for recovery, include the catalog
file.  When evaluating snapshots for complete-ness, check for the
presence of the catalog file and a valid CRC.
ENG-4576: Add the catalog jar file pass to SpecificSnapshotFilter for
consistency's sake, even though the current callers don't need the
catalog.
Merge pull request #464 from VoltDB/eng4576

ENG-4576: Include catalog sanity checks in snapshot completeness criteria
Add some debug logging to StoredProcedureInvocation
Fix an issue Phil reported where the client accidentally kills apprunner.
Merge remote-tracking branch 'origin/master' into uac-fixes