Use a WATCHDOG_WARNING for "FileField was trying to display the file %file, but it does not exist."

The following error message that gets sent to the watchdog:

FileField was trying to display the file %file, but it does not exist. - should use WATCHDOG_WARNING

Should really use either WATCHDOG_WARNING or WATCHDOG_ERROR. Currently it doesn't define a watchdog level, so it is defaulting to using WATCHDOG_NOTICE. When using syslog.module an application like PHPLogCon to analyse the generated Drupal watchdog log files, the above error message shows up in the log in green (green = ok)! Using a more appropriate error level would make the message flag up in orange or red, and would make identifying problems a lot easier. My patch uses the WARNING level, but I'll leave it up to you to decide if that should be an error or warning.

Patch attached :)