HTable MetricsTableLatencies not remove trigger memory leak

MetricsTableLatenciesImpl  histogramsByTable only put but not remove.Maybe we should remove it when table disabled.

supplement:

MetricsTableQueryMeterImpl metersByTable has the same problem.

Recurrence steps:

1. create table: create 'student','data'
2. write data: put 'student','2015001','data:name','Zhangsan'
3. disable table: disable 'student'
4. drop table: drop 'student'
5. visit regionserver:port/jmx
6. search Namespace_default_table_student_metric

Table is deleted, the latency data of the deleted table always in the /jmx endpoint.