kiji-schema: SCHEMA-623. LeaseException in HBaseKijiRowScanner

 - HBaseKijiRowScanner also catches LeaseException in addition to ScannerTimeoutException.

issue: https://jira.kiji.org/browse/SCHEMA-623
review: https://review.kiji.org/r/1535
commit: https://github.com/kijiproject/kiji-schema/commit/ade150adcd06f3d7e45f1f2a5406b892387cb2e4