[BUGFIX] Exception when deleted file is in clipboard

When a file is deleted while it is part of a clipboard, an exception is
thrown when the clipboard is reconstituted. This exception has to be
catched, otherwise the file module will be unusable.

Change-Id: I8849644ffa7b78559c1797d85ce3cc6e01d03a74
Resolves: #43906
Releases: 6.1, 6.0
Reviewed-on: https://review.typo3.org/18191
Reviewed-by: Thomas Scheibitz
Tested-by: Thomas Scheibitz
Reviewed-by: Wouter Wolters
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn