Catch possible NPE in FileSupport.delete()
For some reason we got an NPE here:
In this code in FileSupport.delete()
it appears that children is null, which can happen:
if the file is not a directory (possibly a race condition where the directory has just been deleted) or an I/O error occurs.
Either way, as failing to delete a directory is relatively harmless, we should check for NPE there rather than let the workflow fail as a result.