LU-13811 client: don't panic for mgs evictions

LU-13811 client: don't panic for mgs evictions

Avoid client panics for MGS evictions.
Create a function to check if the eviction is coming
from an MGS, and if so to ignore it.

Rework dump_on_eviction and lbug_on_eviction so
all logic is handled in one place.

Test-Parameters: trivial
HPE-bug-id: LUS-197
Signed-off-by: Alexander Boyko <alexander.boyko@hpe.com>
Signed-off-by: Ben Evans <jevans@cray.com>
Change-Id: Iaa8b06f52fa22ac891b569bc8a2271c8e1e63a3b
Reviewed-on: https://review.whamcloud.com/43655
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andriy Skulysh <askulysh@gmail.com>
Reviewed-by: Alexander Zarochentsev <alexander.zarochentsev@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>