LU-10232 lov: call cl_object_attr_get under cl_attr lock

LU-10232 lov: call cl_object_attr_get under cl_attr lock

cl_object_attr_get() must be called under cl_object_attr_lock
get. There is place in lov_getstripe where it is called
without that lock.

Signed-off-by: Mikhail Pershin <mike.pershin@intel.com>
Change-Id: Ia0a2322ba4ff0ff4affb081375cb108fbf2988c4
Reviewed-on: https://review.whamcloud.com/30052
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>