LU-2753 llite: check alloc in ll_file_data_get, ll_dir_ioctl

LU-2753 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.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I122db2cede770261d75af209e92aa60d86ea85f2
Reviewed-on: http://review.whamcloud.com/5845
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.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>