staging: lustre: hsm: permission checks for HSM ioctl operations

In the LL_IOC_HSM_CT_START case of ll_dir_ioctl() require
CAP_SYS_ADMIN, since the local handler for this ioctl may modify the
global KUC table.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3866
Reviewed-on: http://review.whamcloud.com/7565


Reviewed-by: Aurelien Degremont <aurelien.degremont@cea.fr>
Reviewed-by: Faccini Bruno <bruno.faccini@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>