LU-18595 osd-ldiskfs: use local fake file for iteration

LU-18595 osd-ldiskfs: use local fake file for iteration

LU-13783 introduced the alloc_file_pseudo() for directory iteration.
It leads to many file descriptors for a kernel and a special
logic to drop it LU-16973.

One of the reason of alloc_file_pseudo() was a security_alloc() call.
However we could initialize iteration like kernel and skip
security checks for a pseudo files.

HPE-bug-id: LUS-12253
Fixes: b0f150eba4c2 ("LU-13783 osd-ldiskfs: use alloc_file_pseudo to create fake files")
Signed-off-by: Alexander Boyko <alexander.boyko@hpe.com>
Change-Id: I67d95d84913520b088578923841065e5b1d8b6df
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/57574
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andrew Perepechko <andrew.perepechko@hpe.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>