HBASE-8298 In shell, provide alias of 'desc' for 'describe'.

* Adds ability to alias commands
* map 'desc' alias to 'describe'

Signed-off-by: Andrew Purtell <apurtell@apache.org>
HBASE-11794 StripeStoreFlusher causes NullPointerException (jeongmin kim)

Amending-Author: Andrew Purtell <apurtell@apache.org>