HBASE-12274 Race between RegionScannerImpl#nextInternal() and RegionScannerImpl#close() may produce null pointer exception
HBASE-12261 Add checkstyle to HBase build process
HBASE-12264 ImportTsv should fail fast if output is not specified and table does not exist (Ashish)
HBASE-12263 RegionServer listens on localhost in distributed cluster when DNS is unavailable (Shaohui)
HBASE-12229 NullPointerException in SnapshotTestingUtils

* Implemented the waitUntilAllRegionsOnline in HBaseTestingUtility#createTable
* Add waitFor around #isTableAvailable call that previously didn't do anything
* Remove unused byte[] hex

Signed-off-by: stack <stack@apache.org>