LU-12598 osd-ldiskfs: always return errors for osd_ios_lf_fill

LU-12598 osd-ldiskfs: always return errors for osd_ios_lf_fill

While working on ARM ldiskfs support it was noticed that
osd_ios_lf_fill() behaves differently then the other olm_filldir
handlers. On failure of osd_lookup_one_len() osd_ios_lf_fill()
silently returns zero when it should return an error code. Change
to return proper error codes and update the cdebug messages.

Change-Id: I528b18aaa7277133875cba5db3150ce34cc6431a
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/37323
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>