LU-5560 security: send file security context for creates

LU-5560 security: send file security context for creates

Send file security context to MDT along with create RPCs. This closes
the insecure window between creation and setting of the security
context that existed previously. It also avoids a potential LDLM hang
which arises from ll_create_it() when we send a MDS_SETXATTR RPC while
holding the lookup+layout lock returned from open.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I21415593b7dd362fecbb18cf90b1dc9fbf1c13db
Reviewed-on: http://review.whamcloud.com/19971
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>