Bug 29156: File missing warning in Koha::UploadedFile for permanent files only

Bug 29156: File missing warning in Koha::UploadedFile for permanent files only

When an uploaded file is deleted, when file does not exist there is a warning :
"Removing record for file.txt within category koha_upload, but file was missing."

For temporary files, this warning is noisy.
For example when they are in /tmp, system reboot deleted them.

I propose to remove this warning for temporary files.

Test plan :
1) Upload a temporary and a permanent file via Tools > Upload
2) Delete the file on server
3) Delete the two files from Tools > Upload
4) Look at warning in log files
=> You see only warning for permanent file

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>