LU-11023 quota: remove quota pool ID

LU-11023 quota: remove quota pool ID

Remove pool ID support in quotas as it is
totally unused. It is also needed to start
implementation of quota pools that may
include 2 type of slaves - OST's or MDT's.
At the first stage quota pools will be the
mirror of LOD pools. Further when/if MDT pools
will appear, these could be aslo used as quota
pools.
The main part of quota pool's is not
changed because it will be used for new quota
pools. Remove qmt's pool hash as pool's look up
mainly will be performed by OST/MDT index and
all code connected with quota pool ID.

Cray-bug-id: LUS-5801
Change-Id: Icb72b69e1d194f23a58fcfbd2655969ad73be46b
Signed-off-by: Sergey Cheremencev <c17829@cray.com>
Reviewed-on: https://review.whamcloud.com/34389
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>