EX-3541 lipe: aggregate LPCC information in lpcc status command

EX-3541 lipe: aggregate LPCC information in lpcc status command

Aggregate LPCC backend information in lpcc status command. Including
the configuration of LPCC, lpcc_purge and stats of lpcc_purge.

Change-Id: I6fd394038b0b9b6279a592bd324b76f90585808e
Signed-off-by: Lei Feng <flei@whamcloud.com>
Test-Parameters: trivial
Reviewed-on: https://review.whamcloud.com/44696
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>