SENTRY-555: Ensure groupName returned for dir objects within prefix but not associated with an authz object is not null
SENTRY-545: Disable privilege cleanup by default (Mike Yoder via Lenni Kuff)
SENTRY-556: Remove NPE logging when Sentry Service is not reachable (Reviewed by: Lenni Kuff)
SENTRY-557: Handle Situation when Metastore restarts Listeners thereby resetting the sequenceCounter (Reviewed by : Lenni Kuff)
SENTRY-553: Privilege implies() failed if parent is server privilge and child privilge is URI privilge (Xiaomeng Huang via Lenni Kuff)
SENTRY-555: Make Metastore sync time period configurable (Arun Suresh via Lenni Kuff and Sravya Tirukkovalur)
SENTRY-552
SENTRY-543
merge fix