staging/lustre/llite: check alloc in ll_file_data_get, ll_dir_ioctl

In ll_file_data_get() and ll_dir_ioctl() return error on failed
allocations.

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2753
Lustre-change: http://review.whamcloud.com/5845


Signed-off-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Sebastien Buisson <sebastien.buisson@bull.net>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>