The mod_http_upload_quota module attempts to delete a directory whenever
it removes a file from that directory. However, if thumbnail creation
is enabled, directories will often contain two files. Therefore, don't
log an info (but only a debug) message if directory removal fails.
mod_http_upload_quota implements two features:
- When a "hard quota" is exceeded during a file upload, old files are
removed until the disk usage equals or falls below the "soft quota".
- Once a day, all uploaded files (and directories) older than a
configurable number of days are deleted.
