Details
Description
A file whose file name includes '-' as a first character cannot be included in backup file when external zip command is specified in administrative page.
That is, if I try to backup files including such kind of a file, no backup file might be generated.
The cause is, the routine, 'clean_filename()', allows a file name to start with '-'.
Therefore, '-' seems to be treated as option argument of external zip command.
IMHO, clean_filename() should not allow a file name to start with '-' and I attached my patch fixing this problem.
Assigning to Petr...