LU-3832 clio: honor O_NOATIME

LU-3832 clio: honor O_NOATIME

Add a ci_noatime bit to struct cl_io. In ll_io_init() set this bit if
O_NOATIME is set in f_flags. Ensure that this bit is propagated down
to lower layers. In osc_io_read_start() don't update atime if this bit
is set. Add sanity test 39n to check that passing O_NOATIME to open()
is honored.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I3e7ab1d777e897ce7840ad6b1b067a571fa2bff4
Reviewed-on: http://review.whamcloud.com/7442
Tested-by: Hudson
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>