LU-11175 osc: serialize access to idle_timeout vs cleanup

LU-11175 osc: serialize access to idle_timeout vs cleanup

use LPROCFS_CLIMP_CHECK() and LPROCFS_CLIMP_EXIT() as cl_import
can disappear due to umount.

Change-Id: I2a067f416691f39cde13cfae8f64ed5769d92041
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/32883
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>