HBASE-23055 Alter hbase:meta (#667)

HBASE-23055 Alter hbase:meta (#667)

Make it so hbase:meta can be altered. TableState for hbase:meta
    is kept in Master. State is in-memory transient so if  Master
    fails, hbase:meta is ENABLED again. hbase:meta schema will be
    bootstrapped from the filesystem. Changes to filesystem schema
    are atomic so we should be ok if Master fails mid-edit (TBD)
    Undoes a bunch of guards that prevented our being able to edit
    hbase:meta. At minimmum, need to add in a bunch of WARNING.

    TODO: Tests, more clarity around hbase:meta table state, and undoing
    references to hard-coded hbase:meta regioninfo.

    M hbase-client/src/main/java/org/apache/hadoop/hbase/MetaTableAccessor.java
     Throw illegal access exception if you try to use MetaTableAccessor
     getting state of the hbase:meta table.

    M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java
     For table state, go to master rather than go to meta direct. Going
     to meta won't work for hbase;meta state. Puts load on Master.

    M hbase-client/src/main/java/org/apache/hadoop/hbase/client/HBaseAdmin.java
     Change isTableDisabled/Enabled implementation to ask the Master instead.
     This will give the Master's TableStateManager's opinion rather than
     client figuring it for themselves reading meta table direct.

    M hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
     TODO: Cleanup in here. Go to master for state, not to meta.

    M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ZKAsyncRegistry.java
     Logging cleanup.

    M hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ZNodePaths.java
     Shutdown access.

    M hbase-server/src/main/java/org/apache/hadoop/hbase/TableDescriptors.java
     Just cleanup.

    M hbase-server/src/main/java/org/apache/hadoop/hbase/master/TableStateManager.java
     Add state holder for hbase:meta.
     Removed unused methods.

    M hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStateStore.java
     Shut down access.

    M hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/DisableTableProcedure.java
     Allow hbase:meta to be disabled.

    M hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/EnableTableProcedure.java
     Allow hbase:meta to be enabled.

 Signed-off-by: Ramkrishna <ramkrishna.s.vasudevan@intel.com>