Incompatible changes called out in release notes on jira.
* Cleaned up references to HLog
* Deprecates HLogKey but maintains it for compatibility
- Moves all Writeable from WALKey to HLogKey
* Adds utility code to CoprocessorHost to help with evolving Coprocessor APIs
* RSRpcServices roll WAL call now requests the non-meta LogRoller roll all logs
- rolls actually happen asynchronously
- deprecated old api (and noted incompatible behavior change)
- modified api in new Admin interface to reflect lack of return values.
* Moved WAL user facing API to "WAL"
- only 1 sync offered
- WALTrailer removed from API
* make provider used by the WALFactory configurable.
* Move all WAL requests to use opaque ids instead of paths
* WALProvider provides API details for implementers and handles creation of WALs.
* Refactor WALActionsListener to have a basic implementation.
* turn MetricsWAL into a WALActionsListener.
* tests that needs FSHLog implementation details use them directly, others just reference provider + factory
- Some tests moved from Large to Medium based on run time.
* pull out wal disabling into its own no-op class
* update region open to delegate to WALFactory
* update performance test tool to allow for multiple regions
* Removed references to meta-specific wals within wal code
- replaced with generic suffixes
- WALFactory maintains a dedicated WALProvider for meta (and so knows about the distinction)
* maintain backwards compat on HLogPrettyPrinter and mark it deprecated.
- made WALPrettyPrinter IA.Private in favor of `bin/hbase wal`
* move WALUtil stuff that's implementation specific to said implementation
- WALUtil now acts as an integration point between the RegionServer and hte WAL code.
Incorporates contributions from v.himanshu.
Signed-off-by: stack <stack@apache.org>