EX-3720 lipe: add test cases for lpcc_purge

EX-3720 lipe: add test cases for lpcc_purge

add sanity test cases for lpcc_purge

Change-Id: I420f461f116c41767340329f02920118bf183673
Signed-off-by: Lei Feng <flei@whamcloud.com>
Test-Parameters: trivial testlist=sanity-pcc env=ONLY=200-202,ONLY_REPEAT=50 \
                 clientextra_install_params="--packages lipe-lpcc"
Test-Parameters: trivial testlist=sanity-pcc env=ONLY=200-202,ONLY_REPEAT=50 \
                 clientextra_install_params="--packages lipe-lpcc"
Reviewed-on: https://review.whamcloud.com/44792
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>