HADOOP-16948. Support infinite lease dirs. (#1925)

* HADOOP-16948. Support single writer dirs.

* HADOOP-16948. Fix findbugs and checkstyle problems.

* HADOOP-16948. Fix remaining checkstyle problems.

* HADOOP-16948. Add DurationInfo, retry policy for acquiring lease, and javadocs

* HADOOP-16948. Convert ABFS client to use an executor for lease ops

* HADOOP-16948. Fix ABFS lease test for non-HNS

* HADOOP-16948. Fix checkstyle and javadoc

* HADOOP-16948. Address review comments

* HADOOP-16948. Use daemon threads for ABFS lease ops

* HADOOP-16948. Make lease duration configurable

* HADOOP-16948. Add error messages to test assertions

* HADOOP-16948. Remove extra isSingleWriterKey call

* HADOOP-16948. Use only infinite lease duration due to cost of renewal ops

* HADOOP-16948. Remove acquire/renew/release lease methods

* HADOOP-16948. Rename single writer dirs to infinite lease dirs

* HADOOP-16948. Fix checkstyle

* HADOOP-16948. Wait for acquire lease future

* HADOOP-16948. Add unit test for acquire lease failure
22 files changed