LU-17817 llapi: avoid potential NULL component

LU-17817 llapi: avoid potential NULL component

Avoid potential NULL dereference for component issue in
llapi_layout_file_open() and llapi_layout_file_comp_add()

CoverityID: 425352 ("Dereferencing 'comp', which is known to be NULL")
HPE-bug-id: LUS-12326
Signed-off-by: Rajeev Mishra <rajeevm@hpe.com>
Change-Id: Id773fdbf031a2d11256140590f570f90da46ec3a
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55028
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>